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authorIngo Molnar <mingo@kernel.org>2015-03-31 10:45:47 +0200
committerIngo Molnar <mingo@kernel.org>2015-03-31 10:45:47 +0200
commit36cbf25dc79cc33d623889cafba2c672b161c1ad (patch)
tree6a48140e49a19ee33d35b8e1d8bf13253aa92442 /drivers/firmware
parentMAINTAINERS: Change the x86 microcode loader maintainer (diff)
parentfirmware: dmi_scan: Prevent dmi_num integer overflow (diff)
downloadlinux-36cbf25dc79cc33d623889cafba2c672b161c1ad.tar.xz
linux-36cbf25dc79cc33d623889cafba2c672b161c1ad.zip
Merge tag 'efi-urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/mfleming/efi into x86/urgent
Pull EFI fix from Matt Fleming: - Fix integer overflow issue in the DMI SMBIOS 3.0 code when calculating the number of DMI table entries. (Jean Delvare) Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'drivers/firmware')
-rw-r--r--drivers/firmware/dmi_scan.c22
1 files changed, 7 insertions, 15 deletions
diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c
index 69fac068669f..2eebd28b4c40 100644
--- a/drivers/firmware/dmi_scan.c
+++ b/drivers/firmware/dmi_scan.c
@@ -86,10 +86,13 @@ static void dmi_table(u8 *buf, u32 len, int num,
int i = 0;
/*
- * Stop when we see all the items the table claimed to have
- * OR we run off the end of the table (also happens)
+ * Stop when we have seen all the items the table claimed to have
+ * (SMBIOS < 3.0 only) OR we reach an end-of-table marker OR we run
+ * off the end of the table (should never happen but sometimes does
+ * on bogus implementations.)
*/
- while ((i < num) && (data - buf + sizeof(struct dmi_header)) <= len) {
+ while ((!num || i < num) &&
+ (data - buf + sizeof(struct dmi_header)) <= len) {
const struct dmi_header *dm = (const struct dmi_header *)data;
/*
@@ -529,21 +532,10 @@ static int __init dmi_smbios3_present(const u8 *buf)
if (memcmp(buf, "_SM3_", 5) == 0 &&
buf[6] < 32 && dmi_checksum(buf, buf[6])) {
dmi_ver = get_unaligned_be16(buf + 7);
+ dmi_num = 0; /* No longer specified */
dmi_len = get_unaligned_le32(buf + 12);
dmi_base = get_unaligned_le64(buf + 16);
- /*
- * The 64-bit SMBIOS 3.0 entry point no longer has a field
- * containing the number of structures present in the table.
- * Instead, it defines the table size as a maximum size, and
- * relies on the end-of-table structure type (#127) to be used
- * to signal the end of the table.
- * So let's define dmi_num as an upper bound as well: each
- * structure has a 4 byte header, so dmi_len / 4 is an upper
- * bound for the number of structures in the table.
- */
- dmi_num = dmi_len / 4;
-
if (dmi_walk_early(dmi_decode) == 0) {
pr_info("SMBIOS %d.%d present.\n",
dmi_ver >> 8, dmi_ver & 0xFF);