From 01deda0152066c6c955f0619114ea6afa070aaec Mon Sep 17 00:00:00 2001 From: Michael Bommarito Date: Sun, 10 May 2026 19:16:56 -0400 Subject: [PATCH] thunderbolt: property: Reject u32 wrap in tb_property_entry_valid() entry->value is u32 and entry->length is u16; the sum is performed in u32 and wraps. A malicious XDomain peer can pick value = 0xffffff00, length = 0x100 so the sum 0x100000000 wraps to 0 and passes the > block_len check. tb_property_parse() then passes entry->value to parse_dwdata() as a dword offset into the property block, reading attacker-directed memory far past the allocation. For TEXT-typed entries with the "deviceid" or "vendorid" keys this lands in xd->device_name / xd->vendor_name and is readable back via the per-XDomain device_name / vendor_name sysfs attributes; the leak is NUL-bounded (kstrdup() stops at the first zero byte) and untargeted (the attacker picks a delta, not an absolute address). DATA-typed entries are parsed into property->value.data but not generically surfaced to userspace. Use check_add_overflow() so a wrapped sum is rejected. Fixes: cdae7c07e3e3 ("thunderbolt: Add support for XDomain properties") Cc: stable@vger.kernel.org Assisted-by: Claude:claude-opus-4-6 Assisted-by: Codex:gpt-5-4 Signed-off-by: Michael Bommarito Signed-off-by: Mika Westerberg --- drivers/thunderbolt/property.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/thunderbolt/property.c b/drivers/thunderbolt/property.c index 50cbfc92fe65..29cd60c11ac4 100644 --- a/drivers/thunderbolt/property.c +++ b/drivers/thunderbolt/property.c @@ -8,6 +8,7 @@ */ #include +#include #include #include #include @@ -52,13 +53,16 @@ static inline void format_dwdata(void *dst, const void *src, size_t dwords) static bool tb_property_entry_valid(const struct tb_property_entry *entry, size_t block_len) { + u32 end; + switch (entry->type) { case TB_PROPERTY_TYPE_DIRECTORY: case TB_PROPERTY_TYPE_DATA: case TB_PROPERTY_TYPE_TEXT: if (entry->length > block_len) return false; - if (entry->value + entry->length > block_len) + if (check_add_overflow(entry->value, entry->length, &end) || + end > block_len) return false; break; -- 2.47.3