| From | Paul Gortmaker <> | Subject | [v2.6.34-stable 090/213] coredump: prevent double-free on an error path in core dumper | Date | Wed, 5 Feb 2014 15:00:45 -0500 |
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From: Denys Vlasenko <vda.linux@googlemail.com>
------------------- This is a commit scheduled for the next v2.6.34 longterm release. http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git If you see a problem with using this for longterm, please comment. -------------------
commit f34f9d186df35e5c39163444c43b4fc6255e39c5 upstream.
In !CORE_DUMP_USE_REGSET case, if elf_note_info_init fails to allocate memory for info->fields, it frees already allocated stuff and returns error to its caller, fill_note_info. Which in turn returns error to its caller, elf_core_dump. Which jumps to cleanup label and calls free_note_info, which will happily try to free all info->fields again. BOOM.
This is the fix.
Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Cc: Venu Byravarasu <vbyravarasu@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> --- fs/binfmt_elf.c | 19 ++++--------------- 1 file changed, 4 insertions(+), 15 deletions(-)
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index c21da8aebe46..eee4dd5a13cc 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1661,30 +1661,19 @@ static int elf_note_info_init(struct elf_note_info *info) return 0; info->psinfo = kmalloc(sizeof(*info->psinfo), GFP_KERNEL); if (!info->psinfo) - goto notes_free; + return 0; info->prstatus = kmalloc(sizeof(*info->prstatus), GFP_KERNEL); if (!info->prstatus) - goto psinfo_free; + return 0; info->fpu = kmalloc(sizeof(*info->fpu), GFP_KERNEL); if (!info->fpu) - goto prstatus_free; + return 0; #ifdef ELF_CORE_COPY_XFPREGS info->xfpu = kmalloc(sizeof(*info->xfpu), GFP_KERNEL); if (!info->xfpu) - goto fpu_free; + return 0; #endif return 1; -#ifdef ELF_CORE_COPY_XFPREGS - fpu_free: - kfree(info->fpu); -#endif - prstatus_free: - kfree(info->prstatus); - psinfo_free: - kfree(info->psinfo); - notes_free: - kfree(info->notes); - return 0; } static int fill_note_info(struct elfhdr *elf, int phdrs, -- 1.8.5.2
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