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@xxxxxxx> Reported-by: Michael Schierl <schierlm@xxxxxx> Link: https://lore.kernel.org/linux-kernel/Zh2K3-HLXOesT_vZ@liuwe-devbox-debian-v2/T/ Tested-by: Michael Schierl <schierlm@xxxxxx> --- Changes since v1: * Also log the offset of the corrupted entry (suggested by Michael Kelley) drivers/firmware/dmi_scan.c | 11 +++++++++++ 1 file changed, 11 insertions(+) --- linux-6.8.orig/drivers/firmware/dmi_scan.c +++ linux-6.8/drivers/firmware/dmi_scan.c @@ -102,6 +102,17 @@ static void dmi_decode_table(u8 *buf, 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 %ld (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 * table in dmi_decode or dmi_string -- Jean Delvare SUSE L3 Support
