Merge patch series "fix integer overflows in filesystem code"

This series from Timo tp Preißl <t.preissl@proton.me> fixes some
(potential) interger overflows in some filesystems by using
__builtin_XXX_overflow helps to catch issues.

Link: https://lore.kernel.org/r/20260109112428.262793-1-t.preissl@proton.me

fs/ext4/ext4_write.c

@@ -108,7 +108,13 @@ int ext4fs_get_bgdtable(void)
 {
 	int status;
 	struct ext_filesystem *fs = get_fs();
-	int gdsize_total = ROUND(fs->no_blkgrp * fs->gdsize, fs->blksz);
+	size_t alloc;
+	size_t gdsize_total;
+
+	if (__builtin_mul_overflow(fs->no_blkgrp, fs->gdsize, &alloc))
+		return -1;
+
+	gdsize_total = ROUND(alloc, fs->blksz);
 	fs->no_blk_pergdt = gdsize_total / fs->blksz;
 
 	/* allocate memory for gdtable */

fs/fs.c

@@ -1059,15 +1059,25 @@ int do_mv(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[],
 	 */
 	if (dirs) {
 		char *src_name = strrchr(src, '/');
-		int dst_len;
 
 		if (src_name)
 			src_name += 1;
 		else
 			src_name = src;
 
-		dst_len = strlen(dst);
-		new_dst = calloc(1, dst_len + strlen(src_name) + 2);
+		size_t dst_len = strlen(dst);
+		size_t src_len = strlen(src_name);
+		size_t total;
+
+		if (__builtin_add_overflow(dst_len, src_len, &total) ||
+		    __builtin_add_overflow(total, 2, &total)) {
+			return 0;
+		}
+
+		new_dst = calloc(1, total);
+		if (!new_dst)
+			return 0;
+
 		strcpy(new_dst, dst);
 
 		/* If there is already a trailing slash, don't add another */

fs/squashfs/sqfs.c

@@ -255,10 +255,14 @@ static char *sqfs_concat_tokens(char **token_list, int token_count)
 {
 	char *result;
 	int i, length = 0, offset = 0;
+	size_t alloc;
 
 	length = sqfs_get_tokens_length(token_list, token_count);
 
-	result = malloc(length + 1);
+	if (__builtin_add_overflow(length, 1, &alloc))
+		return 0;
+
+	result = malloc(alloc);
 	if (!result)
 		return NULL;
 

fs/zfs/zfs.c

@@ -1617,6 +1617,7 @@ zfs_nvlist_lookup_nvlist(char *nvlist, char *name)
 	char *ret;
 	size_t size;
 	int found;
+	size_t alloc;
 
 	found = nvlist_find_value(nvlist, name, DATA_TYPE_NVLIST, &nvpair,
 							  &size, 0);
@@ -1627,7 +1628,10 @@ zfs_nvlist_lookup_nvlist(char *nvlist, char *name)
 	 * nvlist to hold the encoding method, and two zero uint32's after the
 	 * nvlist as the NULL terminator.
 	 */
-	ret = calloc(1, size + 3 * sizeof(uint32_t));
+	if (__builtin_add_overflow(size, 3 * sizeof(uint32_t), &alloc))
+		return 0;
+
+	ret = calloc(1, alloc);
 	if (!ret)
 		return 0;
 	memcpy(ret, nvlist, sizeof(uint32_t));