Messages in this thread Patch in this message | ![/](/images/icornerl.gif) | | Date | Thu, 18 Apr 2024 14:27:34 +0200 | From | Jean Delvare <> | Subject | [PATCH v2] firmware: dmi: Stop decoding on broken entry |
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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> Reported-by: Michael Schierl <schierlm@gmx.de> Link: https://lore.kernel.org/linux-kernel/Zh2K3-HLXOesT_vZ@liuwe-devbox-debian-v2/T/ Tested-by: Michael Schierl <schierlm@gmx.de> --- 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
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