linux-ext4 - Re: [PATCH 04/25] libext2fs: reject 64bit badblocks numbers

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Date:	Wed, 23 Oct 2013 19:58:10 -0400
From:	Theodore Ts'o <tytso@....edu>
To:	Lukáš Czerner <lczerner@...hat.com>
Cc:	"Darrick J. Wong" <darrick.wong@...cle.com>,
	linux-ext4@...r.kernel.org
Subject: Re: [PATCH 04/25] libext2fs: reject 64bit badblocks numbers

On Wed, Oct 23, 2013 at 05:24:00PM +0200, Lukáš Czerner wrote:
> 
> 1ULL << 32 is not 32bit number. You need
> 
> 	if (blockno >= 1ULL << 32)

I fixed up this patch like this (which should also be easier for the
compiler to optimize).

						- Ted

>From d87f198ca3250c9dff6a4002cd2bbbb5ab6f113a Mon Sep 17 00:00:00 2001
From: "Darrick J. Wong" <darrick.wong@...cle.com>
Date: Wed, 23 Oct 2013 19:43:32 -0400
Subject: [PATCH] libext2fs: reject 64bit badblocks numbers

Don't accept block numbers larger than 2^32 for the badblocks list,
and don't run badblocks on them either.

Signed-off-by: Darrick J. Wong <darrick.wong@...cle.com>
Signed-off-by: Theodore Ts'o <tytso@....edu>
---
 lib/ext2fs/read_bb_file.c |  7 +++++--
 misc/badblocks.c          | 21 ++++++++++++++++++---
 2 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/lib/ext2fs/read_bb_file.c b/lib/ext2fs/read_bb_file.c
index 7d7bb7a..8d1ad1a 100644
--- a/lib/ext2fs/read_bb_file.c
+++ b/lib/ext2fs/read_bb_file.c
@@ -39,7 +39,7 @@ errcode_t ext2fs_read_bb_FILE2(ext2_filsys fs, FILE *f,
 					       void *priv_data))
 {
 	errcode_t	retval;
-	blk_t		blockno;
+	blk64_t		blockno;
 	int		count;
 	char		buf[128];
 
@@ -55,9 +55,12 @@ errcode_t ext2fs_read_bb_FILE2(ext2_filsys fs, FILE *f,
 	while (!feof (f)) {
 		if (fgets(buf, sizeof(buf), f) == NULL)
 			break;
-		count = sscanf(buf, "%u", &blockno);
+		count = sscanf(buf, "%llu", &blockno);
 		if (count <= 0)
 			continue;
+		/* Badblocks isn't going to be updated for 64bit */
+		if (blockno >> 32)
+			return EOVERFLOW;
 		if (fs &&
 		    ((blockno < fs->super->s_first_data_block) ||
 		     (blockno >= ext2fs_blocks_count(fs->super)))) {
diff --git a/misc/badblocks.c b/misc/badblocks.c
index c9e47c7..432c17b 100644
--- a/misc/badblocks.c
+++ b/misc/badblocks.c
@@ -1047,6 +1047,7 @@ int main (int argc, char ** argv)
 				  unsigned int);
 	int open_flag;
 	long sysval;
+	blk64_t inblk;
 
 	setbuf(stdout, NULL);
 	setbuf(stderr, NULL);
@@ -1200,10 +1201,17 @@ int main (int argc, char ** argv)
 		first_block = parse_uint(argv[optind], _("first block"));
 	} else first_block = 0;
 	if (first_block >= last_block) {
-	    com_err (program_name, 0, _("invalid starting block (%lu): must be less than %lu"),
-		     (unsigned long) first_block, (unsigned long) last_block);
+	    com_err (program_name, 0, _("invalid starting block (%llu): must be less than %llu"),
+		     first_block, last_block);
 	    exit (1);
 	}
+	/* ext2 badblocks file can't handle large values */
+	if (last_block >> 32) {
+		com_err(program_name, EOVERFLOW,
+			_("invalid end block (%llu): must be 32-bit value"),
+			last_block);
+		exit(1);
+	}
 	if (w_flag)
 		check_mount(device_name);
 
@@ -1262,13 +1270,20 @@ int main (int argc, char ** argv)
 
 	if (in) {
 		for(;;) {
-			switch(fscanf (in, "%u\n", &next_bad)) {
+			switch (fscanf(in, "%llu\n", &inblk)) {
 				case 0:
 					com_err (program_name, 0, "input file - bad format");
 					exit (1);
 				case EOF:
 					break;
 				default:
+					if (inblk >> 32) {
+						com_err(program_name,
+							EOVERFLOW,
+							_("while adding to in-memory bad block list"));
+						exit(1);
+					}
+					next_bad = inblk;
 					errcode = ext2fs_badblocks_list_add(bb_list,next_bad);
 					if (errcode) {
 						com_err (program_name, errcode, _("while adding to in-memory bad block list"));
-- 
1.7.12.rc0.22.gcdd159b

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