Messages in this thread Patch in this message | | | From | Denys Vlasenko <> | Subject | [PATCH] coredump: prevent double-free on an error path in core dumper | Date | Wed, 12 Sep 2012 13:37:25 +0200 |
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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> --- fs/binfmt_elf.c | 19 ++++--------------- 1 files changed, 4 insertions(+), 15 deletions(-)
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 760d7f5..1b4efbc 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1695,30 +1695,19 @@ 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, -- 1.7.7.6
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