The 'acpiid' buffer in the parse_ivrs_acpihid function may overflow, because the string specifier in the format string sscanf() has no width limitation.

Found by InfoTeCS on behalf of Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: ca3bf5d47cec ("iommu/amd: Introduces ivrs_acpihid kernel parameter") Cc: stable@vger.kernel.org Signed-off-by: Ilia.Gavrilov Ilia.Gavrilov@infotecs.ru --- V2: Fix typo in the subject drivers/iommu/amd/init.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c index 467b194975b3..19a46b9f7357 100644 --- a/drivers/iommu/amd/init.c +++ b/drivers/iommu/amd/init.c @@ -3475,15 +3475,26 @@ static int __init parse_ivrs_hpet(char *str) return 1; }

+#define ACPIID_LEN (ACPIHID_UID_LEN + ACPIHID_HID_LEN) + static int __init parse_ivrs_acpihid(char *str) { u32 seg = 0, bus, dev, fn; char *hid, *uid, *p, *addr; - char acpiid[ACPIHID_UID_LEN + ACPIHID_HID_LEN] = {0}; + char acpiid[ACPIID_LEN] = {0}; int i;

addr = strchr(str, '@'); if (!addr) { + addr = strchr(str, '='); + if (!addr) + goto not_found; + + ++addr; + + if (strlen(addr) > ACPIID_LEN) + goto not_found; + if (sscanf(str, "[%x:%x.%x]=%s", &bus, &dev, &fn, acpiid) == 4 || sscanf(str, "[%x:%x:%x.%x]=%s", &seg, &bus, &dev, &fn, acpiid) == 5) { pr_warn("ivrs_acpihid%s option format deprecated; use ivrs_acpihid=%s@%04x:%02x:%02x.%d instead\n", @@ -3496,6 +3507,9 @@ static int __init parse_ivrs_acpihid(char *str) /* We have the '@', make it the terminator to get just the acpiid */ *addr++ = 0;

+ if (strlen(str) > ACPIID_LEN + 1) + goto not_found; + if (sscanf(str, "=%s", acpiid) != 1) goto not_found;