Re: [PATCH V5] Fix NULL dereference in super_by_fd

[Jes Sorensen <jes@trained-monkey.org>]

On 2/26/23 22:12, Li Xiao Keng wrote:
> When we create 100 partitions (major is 259 not 254) in a raid device,
> mdadm may coredump:
> 
> Core was generated by `/usr/sbin/mdadm --detail --export /dev/md1p7'.
> Program terminated with signal SIGSEGV, Segmentation fault.
> #0  __strlen_avx2_rtm () at ../sysdeps/x86_64/multiarch/strlen-avx2.S:74
> 74		VPCMPEQ	(%rdi), %ymm0, %ymm1
> (gdb) bt
> #0  __strlen_avx2_rtm () at ../sysdeps/x86_64/multiarch/strlen-avx2.S:74
> #1  0x00007fbb9a7e4139 in __strcpy_chk (dest=dest@entry=0x55d55d6a13ac "", src=0x0, destlen=destlen@entry=32) at strcpy_chk.c:28
> #2  0x000055d55ba1766d in strcpy (__src=<optimized out>, __dest=0x55d55d6a13ac "") at /usr/include/bits/string_fortified.h:79
> #3  super_by_fd (fd=fd@entry=3, subarrayp=subarrayp@entry=0x7fff44dfcc48) at util.c:1289
> #4  0x000055d55ba273a6 in Detail (dev=0x7fff44dfef0b "/dev/md1p7", c=0x7fff44dfe440) at Detail.c:101
> #5  0x000055d55ba0de61 in misc_list (c=<optimized out>, ss=<optimized out>, dump_directory=<optimized out>, ident=<optimized out>, devlist=<optimized out>) at mdadm.c:1959
> #6  main (argc=<optimized out>, argv=<optimized out>) at mdadm.c:1629
> 
> The direct cause is fd2devnm returning NULL, so add a check.
> 
> Signed-off-by: Li Xiao Keng <lixiaokeng@huawei.com>
> Signed-off-by: Wu Guang Hao <wuguanghao3@huawei.com>
> ---
> V1->V2: When fd2devnm return NULL, super_by_fd return NULL but not an
> incomplete 'st' entry. At the same time, add a check in map_by_devnm
> to avoid coredump.
> 
> V2->V3: Fix style issues.
> V3->V4: Change strcpy() to strncpy().
> V4->V5: Move changelog to the location after '---'
> 
>  mapfile.c | 4 ++++
>  util.c    | 7 ++++++-
>  2 files changed, 10 insertions(+), 1 deletion(-)
>

Applied!

Thanks,
Jes