[PATCH v2 8/8] tools/include: fix signed shift overflow in 32-bit unaligned accessors

[Leizhen Zhang]

In __get_unaligned_le32() and __get_unaligned_be32() the most significant
byte is promoted to int before being shifted left by 24. If the byte is
0x80 or higher, the result does not fit in an int, which is undefined
behaviour. This happens for every kernel virtual address, e.g. in
sorttable, and UBSan reports:

  tools/include/tools/le_byteshift.h:14: runtime error: left shift of
  255 by 24 places cannot be represented in type 'int'

Cast the byte to uint32_t before shifting.

Fixes: a07f7672d7cf ("tools/include: Add byteshift headers for endian access")
Assisted-by: Claude:claude-opus-5-5 UBSan
Signed-off-by: Leizhen Zhang <lzsx618@xxxxxxxxx>
---
v2:
 - Use my real name in the From and Signed-off-by lines. No code
   changes.

v1: https://lore.kernel.org/r/20261005104050.1786222-10-lzsx618@xxxxxxxxx

 tools/include/tools/be_byteshift.h | 2 +-
 tools/include/tools/le_byteshift.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/include/tools/be_byteshift.h b/tools/include/tools/be_byteshift.h
index f7d1d16989..2bda8d199c 100644
--- a/tools/include/tools/be_byteshift.h
+++ b/tools/include/tools/be_byteshift.h
@@ -11,7 +11,7 @@ static inline uint16_t __get_unaligned_be16(const uint8_t *p)
 
 static inline uint32_t __get_unaligned_be32(const uint8_t *p)
 {
-	return p[0] << 24 | p[1] << 16 | p[2] << 8 | p[3];
+	return (uint32_t)p[0] << 24 | p[1] << 16 | p[2] << 8 | p[3];
 }
 
 static inline uint64_t __get_unaligned_be64(const uint8_t *p)
diff --git a/tools/include/tools/le_byteshift.h b/tools/include/tools/le_byteshift.h
index dc8565f397..e5c78a48a7 100644
--- a/tools/include/tools/le_byteshift.h
+++ b/tools/include/tools/le_byteshift.h
@@ -11,7 +11,7 @@ static inline uint16_t __get_unaligned_le16(const uint8_t *p)
 
 static inline uint32_t __get_unaligned_le32(const uint8_t *p)
 {
-	return p[0] | p[1] << 8 | p[2] << 16 | p[3] << 24;
+	return p[0] | p[1] << 8 | p[2] << 16 | (uint32_t)p[3] << 24;
 }
 
 static inline uint64_t __get_unaligned_le64(const uint8_t *p)
-- 
2.34.1