From: Jason Baron <jbaron@xxxxxxxxxx> Subject: binfmt_elf: use vmalloc() for allocation of vma_filesz We have observed page allocations failures of order 4 during core dump while trying to allocate vma_filesz. This results in a useless core file of size 0. To improve reliability use vmalloc(). Note that the vmalloc() allocation is bounded by sysctl_max_map_count, which is 65,530 by default. So with a 4k page size, and 8 bytes per seg, this is a max of 128 pages or an order 7 allocation. Other parts of the core dump path, such as fill_files_note() are already using vmalloc() for presumably similar reasons. Link: http://lkml.kernel.org/r/1479745791-17611-1-git-send-email-jbaron@xxxxxxxxxx Signed-off-by: Jason Baron <jbaron@xxxxxxxxxx> Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/binfmt_elf.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff -puN fs/binfmt_elf.c~binfmt_elf-use-vmalloc-for-allocation-of-vma_filesz fs/binfmt_elf.c --- a/fs/binfmt_elf.c~binfmt_elf-use-vmalloc-for-allocation-of-vma_filesz +++ a/fs/binfmt_elf.c @@ -2204,7 +2204,9 @@ static int elf_core_dump(struct coredump dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE); - vma_filesz = kmalloc_array(segs - 1, sizeof(*vma_filesz), GFP_KERNEL); + if (segs - 1 > ULONG_MAX / sizeof(*vma_filesz)) + goto end_coredump; + vma_filesz = vmalloc((segs - 1) * sizeof(*vma_filesz)); if (!vma_filesz) goto end_coredump; @@ -2311,7 +2313,7 @@ end_coredump: cleanup: free_note_info(&info); kfree(shdr4extnum); - kfree(vma_filesz); + vfree(vma_filesz); kfree(phdr4note); kfree(elf); out: _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
