5.4-stable review patch. If anyone has any objections, please let me know.
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From: Dan Carpenter dan.carpenter@linaro.org
commit 55cf2f4b945f6a6416cc2524ba740b83cc9af25a upstream.
Most of these sizes and counts are capped at 256MB so the math doesn't result in an integer overflow. The "relocs" count needs to be checked as well. Otherwise on 32bit systems the calculation of "full_data" could be wrong.
full_data = data_len + relocs * sizeof(unsigned long);
Fixes: c995ee28d29d ("binfmt_flat: prevent kernel dammage from corrupted executable headers") Cc: stable@vger.kernel.org Signed-off-by: Dan Carpenter dan.carpenter@linaro.org Acked-by: Nicolas Pitre npitre@baylibre.com Link: https://lore.kernel.org/r/5be17f6c-5338-43be-91ef-650153b975cb@stanley.mount... Signed-off-by: Kees Cook kees@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/binfmt_flat.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/binfmt_flat.c +++ b/fs/binfmt_flat.c @@ -529,7 +529,7 @@ static int load_flat_file(struct linux_b * 28 bits (256 MB) is way more than reasonable in this case. * If some top bits are set we have probable binary corruption. */ - if ((text_len | data_len | bss_len | stack_len | full_data) >> 28) { + if ((text_len | data_len | bss_len | stack_len | relocs | full_data) >> 28) { pr_err("bad header\n"); ret = -ENOEXEC; goto err;