From 44ec70489f377d1fa9f4e19aed95a7e39da7d93d Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Thu, 4 Jul 2024 14:34:35 +0200 Subject: [PATCH] vmm: make sure we can handle smbios objects without variable part An smbios object with no variable part is a special case, it's just suffixed with two NUL btes. handle that properly. This is inspired by a similar fix from https://github.com/systemd/systemd/pull/29726 --- src/boot/efi/vmm.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/src/boot/efi/vmm.c b/src/boot/efi/vmm.c index 0f268a1512b..87b692cc856 100644 --- a/src/boot/efi/vmm.c +++ b/src/boot/efi/vmm.c @@ -242,13 +242,21 @@ static const SmbiosHeader *get_smbios_table(uint8_t type, uint64_t *ret_size_lef size -= header->length; p += header->length; - /* Skip over string table. */ + /* Special case: if there are no strings appended, we'll see two NUL bytes, skip over them */ + if (size >= 2 && p[0] == 0 && p[1] == 0) { + size -= 2; + p += 2; + continue; + } + + /* Skip over a populated string table. */ + bool first = true; for (;;) { const uint8_t *e = memchr(p, 0, size); if (!e) return NULL; - if (e == p) {/* Double NUL byte means we've reached the end of the string table. */ + if (!first && e == p) {/* Double NUL byte means we've reached the end of the string table. */ p++; size--; break; @@ -256,6 +264,7 @@ static const SmbiosHeader *get_smbios_table(uint8_t type, uint64_t *ret_size_lef size -= e + 1 - p; p = e + 1; + first = false; } } -- 2.47.3