Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
Pre-existing issues: - [High] Incomplete Fix / Integer Truncation Leading to Heap Overflow -- commit 2d027c4ee8625f17122dea0afb65c1e4b21ae531 Author: Masami Hiramatsu (Google) <[email protected]> tools/bootconfig: Fix integer overflow in size check This commit modifies the size check in load_xbc_from_initrd() to prevent an integer overflow on 32-bit systems. It changes the condition to subtract BOOTCONFIG_FOOTER_SIZE from stat.st_size instead of adding it to the bootconfig size. Closes: https://lore.kernel.org/all/[email protected]/ > diff --git a/tools/bootconfig/main.c b/tools/bootconfig/main.c > index 7dc9fff9b6370..b380ad6777faa 100644 > --- a/tools/bootconfig/main.c > +++ b/tools/bootconfig/main.c > @@ -218,7 +218,7 @@ static int load_xbc_from_initrd(int fd, char **buf) > csum = le32toh(csum); > > /* Wrong size error */ > - if (stat.st_size < size + BOOTCONFIG_FOOTER_SIZE) { > + if (size > stat.st_size - BOOTCONFIG_FOOTER_SIZE) { [Severity: High] This is a pre-existing issue, but the fix doesn't seem to completely resolve the integer truncation and heap overflow vulnerabilities. Can this size check still be bypassed for large files? Since stat.st_size is a 64-bit off_t, if the file size is larger than 4.29 GB, stat.st_size - BOOTCONFIG_FOOTER_SIZE can exceed UINT32_MAX. A corrupted uint32_t size of 0xFFFFFFFF would bypass this check because it is always smaller than the right side. If bypassed, does passing 0xFFFFFFFF to load_xbc_fd() cause an integer truncation and heap overflow? tools/bootconfig/main.c:load_xbc_fd() { ... static int load_xbc_fd(int fd, char **buf, int size) ... *buf = malloc(size + 1); if (!*buf) return -ENOMEM; ret = read(fd, *buf, size); ... (*buf)[size] = '\0'; ... } Because size is an int, 0xFFFFFFFF is truncated to -1. This results in malloc(0) which returns a valid heap chunk. The read() call then receives -1 which gets cast to SIZE_MAX, overflowing the heap chunk. Finally, a null byte is written to a negative array index (-1), causing an out-of-bounds write. Does this same vulnerability also affect load_xbc_file() when processing standalone files >= 2GB? tools/bootconfig/main.c:load_xbc_file() { ... ret = fstat(fd, &stat); ... ret = load_xbc_fd(fd, buf, stat.st_size); ... } This implicitly truncates the 64-bit off_t stat.st_size into the 32-bit int size parameter of load_xbc_fd(). > pr_err("bootconfig size is too big\n"); > return -E2BIG; > } -- Sashiko AI review ยท https://sashiko.dev/#/patchset/178900024679.183840.10345859264677533824.stgit@devnote2?part=1
