Commit 729dc340 authored by Ben Hutchings's avatar Ben Hutchings Committed by Masami Hiramatsu (Google)
Browse files

bootconfig: Fix negative seeks on 32-bit with LFS enabled 

Commit 26dda576 "tools/bootconfig: Cleanup bootconfig footer size
calculations" replaced some expressions of type int with the
BOOTCONFIG_FOOTER_SIZE macro, which expands to an expression of type
size_t, which is unsigned.

On 32-bit architectures with LFS enabled (i.e. off_t is 64-bit), the
seek offset of -BOOTCONFIG_FOOTER_SIZE now turns into a positive
value.

Fix this by casting the size to off_t before negating it.

Just in case someone changes BOOTCONFIG_MAGIC_LEN to have type size_t
later, do the same thing to the seek offset of -BOOTCONFIG_MAGIC_LEN.

Link: https://lore.kernel.org/all/aKHlevxeg6Y7UQrz@decadent.org.uk/



Fixes: 26dda576 ("tools/bootconfig: Cleanup bootconfig footer size calculations")
Signed-off-by: default avatarBen Hutchings <benh@debian.org>
Signed-off-by: default avatarMasami Hiramatsu (Google) <mhiramat@kernel.org>
parent c17b750b

tools/bootconfig/main.c

+2 −2
Original line number Diff line number Diff line
@@ -193,7 +193,7 @@ static int load_xbc_from_initrd(int fd, char **buf) 
	if (stat.st_size < BOOTCONFIG_FOOTER_SIZE)

		return 0;



	if (lseek(fd, -BOOTCONFIG_MAGIC_LEN, SEEK_END) < 0)

	if (lseek(fd, -(off_t)BOOTCONFIG_MAGIC_LEN, SEEK_END) < 0)

		return pr_errno("Failed to lseek for magic", -errno);



	if (read(fd, magic, BOOTCONFIG_MAGIC_LEN) < 0)
@@ -203,7 +203,7 @@ static int load_xbc_from_initrd(int fd, char **buf) 
	if (memcmp(magic, BOOTCONFIG_MAGIC, BOOTCONFIG_MAGIC_LEN) != 0)

		return 0;



	if (lseek(fd, -BOOTCONFIG_FOOTER_SIZE, SEEK_END) < 0)

	if (lseek(fd, -(off_t)BOOTCONFIG_FOOTER_SIZE, SEEK_END) < 0)

		return pr_errno("Failed to lseek for size", -errno);



	if (read(fd, &size, sizeof(uint32_t)) < 0)