5.4-stable review patch. If anyone has any objections, please let me know.
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From: Jean Delvare jdelvare@suse.de
[ Upstream commit 0ef11f604503b1862a21597436283f158114d77e ]
If a DMI table entry is shorter than 4 bytes, it is invalid. Due to how DMI table parsing works, it is impossible to safely recover from such an error, so we have to stop decoding the table.
Signed-off-by: Jean Delvare jdelvare@suse.de Link: https://lore.kernel.org/linux-kernel/Zh2K3-HLXOesT_vZ@liuwe-devbox-debian-v2... Reviewed-by: Michael Kelley mhklinux@outlook.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/firmware/dmi_scan.c | 11 +++++++++++ 1 file changed, 11 insertions(+)
diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c index 1e21fc3e9851a..537c104652f71 100644 --- a/drivers/firmware/dmi_scan.c +++ b/drivers/firmware/dmi_scan.c @@ -96,6 +96,17 @@ static void dmi_decode_table(u8 *buf, (data - buf + sizeof(struct dmi_header)) <= dmi_len) { const struct dmi_header *dm = (const struct dmi_header *)data;
+ /* + * If a short entry is found (less than 4 bytes), not only it + * is invalid, but we cannot reliably locate the next entry. + */ + if (dm->length < sizeof(struct dmi_header)) { + pr_warn(FW_BUG + "Corrupted DMI table, offset %zd (only %d entries processed)\n", + data - buf, i); + break; + } + /* * We want to know the total length (formatted area and * strings) before decoding to make sure we won't run off the