Commit 5f99bb93 authored by Alexey Dobriyan's avatar Alexey Dobriyan Committed by Xiangwei Li
Browse files

module: fix [e_shstrndx].sh_size=0 OOB access 

mainline inclusion
from mainline-v5.19-rc1
commit 391e982b
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IBP43S
CVE: CVE-2022-49444

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=391e982bfa632b8315235d8be9c0a81374c6a19c



--------------------------------

It is trivial to craft a module to trigger OOB access in this line:

	if (info->secstrings[strhdr->sh_size - 1] != '\0') {

BUG: unable to handle page fault for address: ffffc90000aa0fff
PGD 100000067 P4D 100000067 PUD 100066067 PMD 10436f067 PTE 0
Oops: 0000 [#1] PREEMPT SMP PTI
CPU: 7 PID: 1215 Comm: insmod Not tainted 5.18.0-rc5-00007-g9bf578647087-dirty #10
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-4.fc34 04/01/2014
RIP: 0010:load_module+0x19b/0x2391

Fixes: ec2a2959 ("module: harden ELF info handling")
Signed-off-by: default avatarAlexey Dobriyan <adobriyan@gmail.com>
[rebased patch onto modules-next]
Signed-off-by: default avatarLuis Chamberlain <mcgrof@kernel.org>

Conflicts:
	kernel/module/main.c
	kernel/module.c
[context conflict]
Signed-off-by: default avatarXiangwei Li <liwei728@huawei.com>
parent c2f6be99

kernel/module.c

+4 −0
Original line number Diff line number Diff line
@@ -3053,6 +3053,10 @@ static int elf_validity_check(struct load_info *info) 
	 * strings in the section safe.

	 */

	info->secstrings = (void *)info->hdr + strhdr->sh_offset;

	if (strhdr->sh_size == 0) {

		pr_err("empty section name table\n");

		return -ENOEXEC;

	}

	if (info->secstrings[strhdr->sh_size - 1] != '\0')

		return -ENOEXEC;