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authorJason Baron <jbaron@akamai.com>2016-12-13 03:46:40 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2016-12-13 05:55:10 +0300
commit30f74aa0854c2d5a331b507b14fe421ba4980511 (patch)
treedb150237a10336a84e822e626e275374a5485b67
parenta82603a8325f89ec53d4c3e249a2e831b747a69d (diff)
downloadlinux-30f74aa0854c2d5a331b507b14fe421ba4980511.tar.xz
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@akamai.com Signed-off-by: Jason Baron <jbaron@akamai.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/binfmt_elf.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 2472af2798c7..e6c1bd443806 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -2204,7 +2204,9 @@ static int elf_core_dump(struct coredump_params *cprm)
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: