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| author | Alexey Dobriyan <adobriyan@gmail.com> | 2022-05-04 12:54:20 +0300 |
|---|---|---|
| committer | Luis Chamberlain <mcgrof@kernel.org> | 2022-05-12 10:29:41 -0700 |
| commit | 391e982bfa632b8315235d8be9c0a81374c6a19c (patch) | |
| tree | 3a1466f8c48a57cd6a1af9abe4a617f4f99ace47 | |
| parent | 99bd9956551b27cb6f5b445abaced7e13b9976cd (diff) | |
| download | linux-391e982bfa632b8315235d8be9c0a81374c6a19c.tar.bz2 | |
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>
| -rw-r--r-- | kernel/module/main.c | 4 |
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; |