The following TPM 2.0 commands are introduced to tss2 to access the
TPM non-volatile memory associated with the NV index handles:
- TPM2_NV_DefineSpace,
- TPM2_NV_UndefineSpace,
- TPM2_NV_ReadPublic,
- TPM2_NV_Read,
- TPM2_NV_Write.
The related marshal/unmarshal functions are also introduced.
Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
grub_tpm2_readpublic() and grub_tpm2_testparms() didn't check
authCommand when marshaling the input data buffer. Currently, there is
no caller using non-NULL authCommand. However, to avoid the potential
issue, the conditional check is added to insert authCommand into the
input buffer if necessary.
Also fix a few pointer checks.
Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The user may need to inspect the TPM 2.0 PCR values with the GRUB shell,
so the new tpm2_dump_pcr command is added to print all PCRs of the
specified bank.
Also update the document for the new command.
Signed-off-by: Gary Lin <glin@suse.com>
Tested-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
PCR mismatch is one common cause of TPM key unsealing fail. Since the
system may be compromised, it is not safe to boot into OS to get the PCR
values and TPM eventlog for the further investigation.
To provide some hints, GRUB now dumps PCRs on policy fail, so the user
can check the current PCR values. PCR 0~15 are chosen to cover the
firmware, bootloader, and OS.
The sample output:
PCR Mismatch! Check firmware and bootloader before typing passphrase!
TPM PCR [sha256]:
00: 17401f37710984c1d8a03a81fff3ab567ae9291bac61e21715b890ee28879738
01: 7a114329ba388445a96e8db2a072785937c1b7a8803ed7cc682b87f3ff3dd7a8
02: 11c2776849e8e24b7d80c926cbc4257871bffa744dadfefd3ed049ce25143e05
03: 6c33b362073e28e30b47302bbdd3e6f9cee4debca3a304e646f8c68245724350
04: 62d38838483ecfd2484ee3a2e5450d8ca3b35fc72cda6a8c620f9f43521c37d1
05: d8a85cb37221ab7d1f2cc5f554dbe0463acb6784b5b8dc3164ccaa66d8fff0e1
06: 9262e37cbe71ed4daf815b4a4881fb7251c9d371092dde827557d5368121e10e
07: 219d542233be492d62b079ffe46cf13396a8c27e520e88b08eaf2e6d3b7e70f5
08: de1f61c973b673e505adebe0d7e8fb65fde6c24dd4ab4fbaff9e28b18df6ecd3
09: c1de7274fa3e879a16d7e6e7629e3463d95f68adcfd17c477183846dccc41c89
10: 0000000000000000000000000000000000000000000000000000000000000000
11: 0000000000000000000000000000000000000000000000000000000000000000
12: 0000000000000000000000000000000000000000000000000000000000000000
13: 0000000000000000000000000000000000000000000000000000000000000000
14: 9ab9ebe4879a7f4dd00c04f37e79cfd69d0dd7a8bcc6b01135525b67676a3e40
15: 0000000000000000000000000000000000000000000000000000000000000000
16: 0000000000000000000000000000000000000000000000000000000000000000
17: ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
18: ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
19: ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
20: ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
21: ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
22: ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
23: 0000000000000000000000000000000000000000000000000000000000000000
error: failed to unseal sealed key (TPM2_Unseal: 0x99d).
error: no key protector provided a usable key for luks (af16e48f-746b-4a12-aae1-c14dcee429e0).
If the user happens to have the PCR values for key sealing, the PCR dump
can be used to identify the changed PCRs and narrow down the scope for
closer inspection.
Please note that the PCR dump is trustworthy only if the GRUB binary is
authentic, so the user has to check the GRUB binary thoroughly before
using the PCR dump.
Signed-off-by: Gary Lin <glin@suse.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Update linux_kernel_params to match the v6.13.7 upstream version of boot_params.
Refactor most things out into structs, as the Linux kernel does.
edid_info should be a struct with "unsigned char dummy[128]" and efi_info should
be a struct as well, starting at 0x1c0. However, for backwards compatibility,
GRUB can have efi_systab at 0x1b8 and padding at 0x1bc (or padding at both spots).
This cuts into the end of edid_info. Make edid_info inline and only make it go
up to 0x1b8.
Signed-off-by: Patrick Colp <patrick.colp@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
In grub_xnu_load_kext_from_dir(), when the call to grub_device_open()
failed, it simply cleaned up previously allocated memory and returned
GRUB_ERR_NONE. However, it neglected to free ctx->newdirname which is
allocated before the call to grub_device_open().
Fixes: CID 473859
Signed-off-by: Lidong Chen <lidong.chen@oracle.com>
Reviewed-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
In grub_cmd_initrd(), initrd_ctx is allocated before calling
grub_relocator_alloc_chunk_align(). When that function fails,
initrd_ctx should be freed before exiting grub_cmd_initrd().
Fixes: CID 473852
Signed-off-by: Lidong Chen <lidong.chen@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Fix memory leaks in make_vg() with new helper functions, free_pv()
and free_lv(). Additionally, correct a check after allocating
comp->segments->nodes that mistakenly checked lv->segments->nodes
instead, likely due to a copy-paste error.
Fixes: CID 473878
Fixes: CID 473884
Fixes: CID 473889
Fixes: CID 473890
Signed-off-by: Lidong Chen <lidong.chen@oracle.com>
Reviewed-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
A regression was introduced recently as a part of the series of
filesystem related patches to address some CVEs found in GRUB.
This issue may cause either an infinite loop at startup when
accessing certain valid NTFS filesystems, or may cause a crash
due to a NULL pointer dereference on systems where NULL address
is invalid (such as may happen when calling grub-mount from
the operating system level).
Correct this issue by checking that at->attr_cur is within bounds
inside find_attr().
Fixes: https://savannah.gnu.org/bugs/?66855
Fixes: aff263187 (fs/ntfs: Fix out-of-bounds read)
Signed-off-by: B Horn <b@horn.uk>
Signed-off-by: Andrew Hamilton <adhamilt@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com
Reviewed-by: Vladimir Serbinenko <phcoder@gmail.com>
The grub_malloc() has been inadvertently removed from the code after it
has been modified to use safe math functions.
Fixes: 4beeff8a (net: Use safe math macros to prevent overflows)
Signed-off-by: Nicolas Frayer <nfrayer@redhat.com>
Tested-by: Marta Lewandowska <mlewando@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Change RMA size from 512 MB to 768 MB which will result in more memory
at boot time for PowerPC. When vTPM, Secure Boot or FADump are enabled
on PowerPC the 512 MB RMA memory is not sufficient for boot. With this
512 MB RMA, GRUB runs out of memory and fails to boot the machine.
Sometimes even usage of CDROM requires more memory for installation and
along with the options mentioned above exhausts the boot memory which
results in boot failures. Increasing the RMA size will resolves multiple
out of memory issues observed on PowerPC machines.
Failure details (GRUB debug console dump):
kern/ieee1275/init.c:550: mm requested region of size 8513000, flags 1
kern/ieee1275/init.c:563: Cannot satisfy allocation and retain minimum runtime space
kern/ieee1275/init.c:550: mm requested region of size 8513000, flags 0
kern/ieee1275/init.c:563: Cannot satisfy allocation and retain minimum runtime space
kern/file.c:215: Closing `/ppc/ppc64/initrd.img' ...
kern/disk.c:297: Closing `ieee1275//vdevice/v-scsi@30000067/disk@8300000000000000'...
kern/disk.c:311: Closing `ieee1275//vdevice/v-scsi@30000067/disk@8300000000000000' succeeded.
kern/file.c:225: Closing `/ppc/ppc64/initrd.img' failed with 3.
kern/file.c:148: Opening `/ppc/ppc64/initrd.img' succeeded.
error: ../../grub-core/kern/mm.c:552:out of memory.
Signed-off-by: Avnish Chouhan <avnish@linux.ibm.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Without this fix the GRUB failed to boot linux with "out of memory" after
trying to run a "search --fs-uuid..." on a system that has 7 ZFS pools
across about 80 drives.
Signed-off-by: Stuart Hayes <stuart.w.hayes@gmail.com>
Reviewed-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Mark cachevol LV's as ignored features, which is true only if they are
configured as "writethrough". This patch does not let GRUB boot from
"writeback" cache-enabled LV's.
Signed-off-by: Patrick Plenefisch <simonpatp@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The LV matching must be done after processing the ignored feature
indirections, as integrity volumes & caches may have several levels
of indirection that the segments must be shifted through.
Signed-off-by: Patrick Plenefisch <simonpatp@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The PV matching must be completely finished before validating a volume,
otherwise referenced RAID stripes may not have PV data applied yet.
This change is required for integrity & cachevol support.
Signed-off-by: Patrick Plenefisch <simonpatp@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The cache_pool is never read or used, remove it.
Signed-off-by: Patrick Plenefisch <simonpatp@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This patch isn't necessary by itself, but when combined with subsequent
patches it enhances readability as ignored_features_lv is then used for
multiple types of extra LV's, not just cache LV's.
Signed-off-by: Patrick Plenefisch <simonpatp@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Like the GNU ls, first print a line with the directory path before printing
files in the directory, which will not have a directory component, but only
if there is more than one argument.
Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
For arguments that are paths to files, print the full path of the file.
Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The modification time for paths to files was not being printed because
the grub_dirhook_info, which contains the mtime, was initialized to NULL.
Instead of calling print_file() directly, use fs->fs_dir() to call
print_file() with a properly filled in grub_dirhook_info. This has the
added benefit of reducing code complexity.
Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Simplify the code by removing logic around which file printer to call.
Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
FreeBSD loader always passes "elf kernel". We currently pass "elf64 kernel"
when loading 64-bit kernel. The -CURRENT, HEAD, kernel accepts only
"elf kernel". Older kernel accepts either.
Tested with FreeBSD and DragonFlyBSD.
Reference: https://cgit.freebsd.org/src/commit/?id=b72ae900d4348118829fe04abdc11b620930c30f
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
When using syntax "hd0,gtp3,dfly1" then ptr points to trailing part, ",dfly1".
So, it's improper to consider it as an invalid partition.
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
grub-core/lib/tss2/tss2_structs.h contains a duplicate typedef as follows:
typedef TPMS_SCHEME_HASH_t TPMS_SCHEME_KDF2_t;
This causes a build failure when compiling with clang. Remove the
duplicate typedef which allows successfully building GRUB with clang.
Signed-off-by: Andrew Hamilton <adhamilt@gmail.com>
Reviewed-by: Ross Philipson <ross.philipson@oracle.com>
Reviewed-by: Gary Lin <glin@suse.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The grub_script_execute_sourcecode() parses and executes code one line
at a time, updating the return code each time because only the last line
determines the final status. However, trailing new lines were also
executed, masking any failure on the previous line. Fix this by only
trying to execute the command when there is actually one present.
This has presumably never been noticed because this code is not used by
regular functions, only in special cases like eval and menu entries. The
latter generally don't return at all, having booted an OS. When failing
to boot, upstream GRUB triggers the fallback mechanism regardless of the
return code.
We noticed the problem while using Red Hat's patches, which change this
behaviour to take account of the return code. In that case, a failure
takes you back to the menu rather than triggering a fallback.
Signed-off-by: James Le Cuirot <jlecuirot@microsoft.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Commit ef7850c757 (fs/xfs: Fix issues found while fuzzing the XFS
filesystem) introduced multiple boundary checks in grub_xfs_iterate_dir()
but handled the error incorrectly returning error code instead of 0.
Fix it. Also change the error message so that it doesn't match the
message in grub_xfs_read_inode().
Fixes: ef7850c757 (fs/xfs: Fix issues found while fuzzing the XFS filesystem)
Signed-off-by: Egor Ignatov <egori@altlinux.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The Linux port of XFS added a few new features in 2024. The existing
GRUB driver doesn't attempt to read or write any of the new metadata,
so, all three can be added to the incompat allowlist.
On the occasion align XFS_SB_FEAT_INCOMPAT_NREXT64 value.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Previously, the number of extent entries was not properly capped based
on the actual available space. This could lead to insufficient reads for
external extents since the computation was based solely on the inline
extent layout.
In this patch, when processing the extent header we determine whether
the header is stored inline, i.e. at inode->blocks.dir_blocks, or in an
external extent block. We then clamp the number of entries accordingly
(using max_inline_ext for inline extents and max_external_ext for
external extent blocks).
This change ensures that only the valid number of extent entries is
processed preventing out-of-bound reads and potential filesystem
corruption.
Fixes: 7e2f750f0a (fs/ext2: Fix out-of-bounds read for inline extents)
Signed-off-by: Michael Chang <mchang@suse.com>
Tested-by: Christian Hesse <mail@eworm.de>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The conditional makes no sense when the two possible expressions have
the same value, so, remove it (perhaps the compiler does it for us but
better to remove it). This change makes spinup argument unused. So, drop
it as well.
Signed-off-by: Leo Sandoval <lsandova@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The Microsoft spec for SPCR says "The base address of the Serial Port
register set described using the ACPI Generic Address Structure, or
0 if console redirection is disabled". So, return early if redirection
is disabled (base address = 0). If this check is not done we may get
invalid ports on machines with redirection disabled and boot may hang
when reading the grub.cfg file.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Leo Sandoval <lsandova@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The pointer returned by grub_elf_file() is not checked to verify it is
not NULL before use. A NULL pointer may be returned when the given file
does not have a valid ELF header.
Fixes: https://savannah.gnu.org/bugs/?61960
Signed-off-by: Glenn Washburn <development@efficientek.com>
Signed-off-by: Lukas Fink <lukas.fink1@gmail.com>
Reviewed-by: Ross Philipson <ross.philipson@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
%s/hueristic/heuristic/
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Ross Philipson <ross.philipson@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The EFI Boot Services can be used after ExitBootServices() call because
the GRUB code still may allocate memory.
An example call stack is:
grub_multiboot_boot
grub_multiboot2_make_mbi
grub_efi_finish_boot_services
b->exit_boot_services
normal_boot
grub_relocator32_boot
grub_relocator_alloc_chunk_align_safe
grub_relocator_alloc_chunk_align
grub_malloc
grub_memalign
grub_mm_add_region_fn
[= grub_efi_mm_add_regions]
grub_efi_allocate_any_pages
grub_efi_allocate_pages_real
b->allocate_pages
This can lead to confusing errors. After ExitBootServices() call
b->allocate_pages may point to the NULL address resulting in something like:
!!!! X64 Exception Type - 01(#DB - Debug) CPU Apic ID - 00000000 !!!!
RIP - 000000000000201F, CS - 0000000000000038, RFLAGS - 0000000000200002
RAX - 000000007F9EE010, RCX - 0000000000000001, RDX - 0000000000000002
RBX - 0000000000000006, RSP - 00000000001CFBEC, RBP - 0000000000000000
RSI - 0000000000000000, RDI - 00000000FFFFFFFF
R8 - 0000000000000006, R9 - 000000007FEDFFB8, R10 - 0000000000000000
R11 - 0000000000000475, R12 - 0000000000000001, R13 - 0000000000000002
R14 - 00000000FFFFFFFF, R15 - 000000007E432C08
DS - 0000000000000030, ES - 0000000000000030, FS - 0000000000000030
GS - 0000000000000030, SS - 0000000000000030
CR0 - 0000000080010033, CR2 - 0000000000000000, CR3 - 000000007FC01000
CR4 - 0000000000000668, CR8 - 0000000000000000
DR0 - 0000000000000000, DR1 - 0000000000000000, DR2 - 0000000000000000
DR3 - 0000000000000000, DR6 - 00000000FFFF0FF0, DR7 - 0000000000000400
GDTR - 000000007F9DE000 0000000000000047, LDTR - 0000000000000000
IDTR - 000000007F470018 0000000000000FFF, TR - 0000000000000000
FXSAVE_STATE - 00000000001CF840
Ideally we would like to avoid all memory allocations after exiting EFI
Boot Services altogether but that requires significant code changes. This
patch adds a simple workaround that resets grub_mm_add_region_fn to NULL
after ExitBootServices() call, so:
- Memory allocations have a better chance of succeeding because grub_memalign()
will try to reclaim the disk cache if it sees a NULL in grub_mm_add_region_fn.
- At worst it will fail to allocate memory but it will explicitly tell users
that it's out of memory, which is still much better than the current
situation where it fails in a fairly random way and triggers a CPU fault.
Signed-off-by: Ruihan Li <lrh2000@pku.edu.cn>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The grub_divmod64() may return 0 but grub_tsc_calibrate_from_pmtimer()
still returns 1 saying calibration succeeded. Of course it is not true.
So, return 0 when grub_divmod64() returns 0. This way other calibration
functions can be called subsequently.
Signed-off-by: Duan Yayong <duanyayong@bytedance.com>
Signed-off-by: Li Yongqiang <liyongqiang@huaqin.com>
Signed-off-by: Sun Ming <simon.sun@huaqin.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Simply returning from grub_cmd_linux() doesn't free "file" resource nor
calls grub_dl_ref(my_mod). Jump to "fail" label for proper cleanup like
other error checks do.
Signed-off-by: Sergii Dmytruk <sergii.dmytruk@3mdeb.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The operation kern_end - kern_start may underflow when we input it into
grub_relocator_alloc_chunk_addr() call. To avoid this we can use safe
math for this subtraction.
Fixes: CID 73845
Signed-off-by: Alec Brown <alec.r.brown@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The Coverity complains that we might overflow into a negative value when
setting linux_params.kernel_alignment to (1 << align). We can remedy
this by casting it to grub_uint32_t.
Fixes: CID 473876
Signed-off-by: Alec Brown <alec.r.brown@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
When the format string, fmt0, includes a positional argument
grub_strtoul() or grub_strtoull() is called to extract the argument
position. However, the returned argument position isn't fully validated.
If the format is something like "%0$x" then these functions return
0 which leads to an underflow in the calculation of the args index, curn.
The fix is to add a check to ensure the extracted argument position is
greater than 0 before computing curn. Additionally, replace one
grub_strtoull() with grub_strtoul() and change curn type to make code
more correct.
Fixes: CID 473841
Signed-off-by: Lidong Chen <lidong.chen@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The current code incorrectly assumes that both the input and the values
returned by grub_strtoul() are always valid which can lead to potential
errors. This fix ensures proper validation to prevent any unintended issues.
Fixes: CID 473843
Signed-off-by: Lidong Chen <lidong.chen@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The Coverity indicates that the variable current_entry might overflow.
To prevent this use safe math when adding GRUB_MENU_PAGE_SIZE to current_entry.
On the occasion fix limiting condition which was broken.
Fixes: CID 473853
Signed-off-by: Alec Brown <alec.r.brown@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The Coverity indicates that GRUB_EHCI_TOGGLE is an int that contains
a negative value and we are using it for the variable token which is
grub_uint32_t. To remedy this we can cast the definition to grub_uint32_t.
Fixes: CID 473851
Signed-off-by: Alec Brown <alec.r.brown@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Update the overflow error messages to make them consistent
across the GRUB code.
Signed-off-by: Lidong Chen <lidong.chen@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
The entry_len is initialized in grub_find_root_devices_from_mountinfo()
to 0 before the while loop iterates through /proc/self/mountinfo. If the
file is empty or contains only invalid entries entry_len remains
0 causing entry_len - 1 in the subsequent for loop initialization
to underflow. To prevent this add a check to ensure entry_len > 0 before
entering the for loop.
Fixes: CID 473877
Signed-off-by: Lidong Chen <lidong.chen@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Ross Philipson <ross.philipson@oracle.com>
The result is initialized to 0 in grub_script_arglist_to_argv().
If the for loop condition is not met both result.args and result.argc
remain 0 causing result.argc - 1 to underflow and/or result.args NULL
dereference. Fix the issues by adding relevant checks.
Fixes: CID 473880
Signed-off-by: Lidong Chen <lidong.chen@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
