From 729dc340a4ed1267774fc8518284e976e2210bdc Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Sun, 17 Aug 2025 16:21:46 +0200 Subject: [PATCH] bootconfig: Fix negative seeks on 32-bit with LFS enabled Commit 26dda5769509 "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: 26dda5769509 ("tools/bootconfig: Cleanup bootconfig footer size calculations") Signed-off-by: Ben Hutchings Signed-off-by: Masami Hiramatsu (Google) --- tools/bootconfig/main.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/tools/bootconfig/main.c b/tools/bootconfig/main.c index 57c669d2aa90..55d59ed507d5 100644 --- a/tools/bootconfig/main.c +++ b/tools/bootconfig/main.c @@ -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) -- 2.25.1