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authorAlexey Dobriyan <adobriyan@gmail.com>2022-05-04 12:54:20 +0300
committerLuis Chamberlain <mcgrof@kernel.org>2022-05-12 10:29:41 -0700
commit391e982bfa632b8315235d8be9c0a81374c6a19c (patch)
tree3a1466f8c48a57cd6a1af9abe4a617f4f99ace47 /kernel/module
parent99bd9956551b27cb6f5b445abaced7e13b9976cd (diff)
module: fix [e_shstrndx].sh_size=0 OOB access
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: ec2a29593c83 ("module: harden ELF info handling") Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> [rebased patch onto modules-next] Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Diffstat (limited to 'kernel/module')
-rw-r--r--kernel/module/main.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/kernel/module/main.c b/kernel/module/main.c
index 6c3b4a846645..23432fabfde8 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -1726,6 +1726,10 @@ 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");
+ goto no_exec;
+ }
if (info->secstrings[strhdr->sh_size - 1] != '\0') {
pr_err("ELF Spec violation: section name table isn't null terminated\n");
goto no_exec;