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authorKees Cook <keescook@chromium.org>2019-09-26 10:15:25 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-09-26 11:38:55 -0700
commit7be3cb019db1cbd5fd5ffe6d64a23fefa4b6f229 (patch)
treedfaa5fd5e0da06616250e8c0c915eac6dbbd8a2b /fs
parent2268419e4c9559ec1e80ee7ae7bd54f8976234cb (diff)
binfmt_elf: Do not move brk for INTERP-less ET_EXEC
When brk was moved for binaries without an interpreter, it should have been limited to ET_DYN only. In other words, the special case was an ET_DYN that lacks an INTERP, not just an executable that lacks INTERP. The bug manifested for giant static executables, where the brk would end up in the middle of the text area on 32-bit architectures. Reported-and-tested-by: Richard Kojedzinszky <richard@kojedz.in> Fixes: bbdc6076d2e5 ("binfmt_elf: move brk out of mmap when doing direct loader exec") Cc: stable@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/binfmt_elf.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index cec3b4146440..ad4c6b1d5074 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1121,7 +1121,8 @@ out_free_interp:
* (since it grows up, and may collide early with the stack
* growing down), and into the unused ELF_ET_DYN_BASE region.
*/
- if (IS_ENABLED(CONFIG_ARCH_HAS_ELF_RANDOMIZE) && !interpreter)
+ if (IS_ENABLED(CONFIG_ARCH_HAS_ELF_RANDOMIZE) &&
+ loc->elf_ex.e_type == ET_DYN && !interpreter)
current->mm->brk = current->mm->start_brk =
ELF_ET_DYN_BASE;

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