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reiserfs: fix buffer overflow with long warning messages 

ReiserFS prepares log messages into a 1024-byte buffer with no bounds
checks.  Long messages, such as the "unknown mount option" warning when
userspace passes a crafted mount options string, overflow this buffer.
This causes KASAN to report a global-out-of-bounds write.

Fix it by truncating messages to the buffer size.

Link: http://lkml.kernel.org/r/20180707203621.30922-1-ebiggers3@gmail.com
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Reported-by: syzbot+b890b3335a4d8c608963@syzkaller.appspotmail.com
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Eric Biggers 2018-07-13 16:59:27 -07:00 committed by Linus Torvalds
parent ffe075132a
commit fe10e398e8
1 changed files with 81 additions and 60 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

141
fs/reiserfs/prints.c
View File

@ -76,83 +76,99 @@ static char *le_type(struct reiserfs_key *key)
}
/* %k */
static void sprintf_le_key(char *buf, struct reiserfs_key *key)
static int scnprintf_le_key(char *buf, size_t size, struct reiserfs_key *key)
{
if (key)
sprintf(buf, "[%d %d %s %s]", le32_to_cpu(key->k_dir_id),
le32_to_cpu(key->k_objectid), le_offset(key),
le_type(key));
return scnprintf(buf, size, "[%d %d %s %s]",
le32_to_cpu(key->k_dir_id),
le32_to_cpu(key->k_objectid), le_offset(key),
le_type(key));
else
sprintf(buf, "[NULL]");
return scnprintf(buf, size, "[NULL]");
}
/* %K */
static void sprintf_cpu_key(char *buf, struct cpu_key *key)
static int scnprintf_cpu_key(char *buf, size_t size, struct cpu_key *key)
{
if (key)
sprintf(buf, "[%d %d %s %s]", key->on_disk_key.k_dir_id,
key->on_disk_key.k_objectid, reiserfs_cpu_offset(key),
cpu_type(key));
return scnprintf(buf, size, "[%d %d %s %s]",
key->on_disk_key.k_dir_id,
key->on_disk_key.k_objectid,
reiserfs_cpu_offset(key), cpu_type(key));
else
sprintf(buf, "[NULL]");
return scnprintf(buf, size, "[NULL]");
}
static void sprintf_de_head(char *buf, struct reiserfs_de_head *deh)
static int scnprintf_de_head(char *buf, size_t size,
struct reiserfs_de_head *deh)
{
if (deh)
sprintf(buf,
"[offset=%d dir_id=%d objectid=%d location=%d state=%04x]",
deh_offset(deh), deh_dir_id(deh), deh_objectid(deh),
deh_location(deh), deh_state(deh));
return scnprintf(buf, size,
"[offset=%d dir_id=%d objectid=%d location=%d state=%04x]",
deh_offset(deh), deh_dir_id(deh),
deh_objectid(deh), deh_location(deh),
deh_state(deh));
else
sprintf(buf, "[NULL]");
return scnprintf(buf, size, "[NULL]");
}
static void sprintf_item_head(char *buf, struct item_head *ih)
static int scnprintf_item_head(char *buf, size_t size, struct item_head *ih)
{
if (ih) {
strcpy(buf,
(ih_version(ih) == KEY_FORMAT_3_6) ? "*3.6* " : "*3.5*");
sprintf_le_key(buf + strlen(buf), &(ih->ih_key));
sprintf(buf + strlen(buf), ", item_len %d, item_location %d, "
"free_space(entry_count) %d",
ih_item_len(ih), ih_location(ih), ih_free_space(ih));
char *p = buf;
char * const end = buf + size;
p += scnprintf(p, end - p, "%s",
(ih_version(ih) == KEY_FORMAT_3_6) ?
"*3.6* " : "*3.5*");
p += scnprintf_le_key(p, end - p, &ih->ih_key);
p += scnprintf(p, end - p,
", item_len %d, item_location %d, free_space(entry_count) %d",
ih_item_len(ih), ih_location(ih),
ih_free_space(ih));
return p - buf;
} else
sprintf(buf, "[NULL]");
return scnprintf(buf, size, "[NULL]");
}
static void sprintf_direntry(char *buf, struct reiserfs_dir_entry *de)
static int scnprintf_direntry(char *buf, size_t size,
struct reiserfs_dir_entry *de)
{
char name[20];
memcpy(name, de->de_name, de->de_namelen > 19 ? 19 : de->de_namelen);
name[de->de_namelen > 19 ? 19 : de->de_namelen] = 0;
sprintf(buf, "\"%s\"==>[%d %d]", name, de->de_dir_id, de->de_objectid);
return scnprintf(buf, size, "\"%s\"==>[%d %d]",
name, de->de_dir_id, de->de_objectid);
}
static void sprintf_block_head(char *buf, struct buffer_head *bh)
static int scnprintf_block_head(char *buf, size_t size, struct buffer_head *bh)
{
sprintf(buf, "level=%d, nr_items=%d, free_space=%d rdkey ",
B_LEVEL(bh), B_NR_ITEMS(bh), B_FREE_SPACE(bh));
return scnprintf(buf, size,
"level=%d, nr_items=%d, free_space=%d rdkey ",
B_LEVEL(bh), B_NR_ITEMS(bh), B_FREE_SPACE(bh));
}
static void sprintf_buffer_head(char *buf, struct buffer_head *bh)
static int scnprintf_buffer_head(char *buf, size_t size, struct buffer_head *bh)
{
sprintf(buf,
"dev %pg, size %zd, blocknr %llu, count %d, state 0x%lx, page %p, (%s, %s, %s)",
bh->b_bdev, bh->b_size,
(unsigned long long)bh->b_blocknr, atomic_read(&(bh->b_count)),
bh->b_state, bh->b_page,
buffer_uptodate(bh) ? "UPTODATE" : "!UPTODATE",
buffer_dirty(bh) ? "DIRTY" : "CLEAN",
buffer_locked(bh) ? "LOCKED" : "UNLOCKED");
return scnprintf(buf, size,
"dev %pg, size %zd, blocknr %llu, count %d, state 0x%lx, page %p, (%s, %s, %s)",
bh->b_bdev, bh->b_size,
(unsigned long long)bh->b_blocknr,
atomic_read(&(bh->b_count)),
bh->b_state, bh->b_page,
buffer_uptodate(bh) ? "UPTODATE" : "!UPTODATE",
buffer_dirty(bh) ? "DIRTY" : "CLEAN",
buffer_locked(bh) ? "LOCKED" : "UNLOCKED");
}
static void sprintf_disk_child(char *buf, struct disk_child *dc)
static int scnprintf_disk_child(char *buf, size_t size, struct disk_child *dc)
{
sprintf(buf, "[dc_number=%d, dc_size=%u]", dc_block_number(dc),
dc_size(dc));
return scnprintf(buf, size, "[dc_number=%d, dc_size=%u]",
dc_block_number(dc), dc_size(dc));
}
static char *is_there_reiserfs_struct(char *fmt, int *what)
@ -189,55 +205,60 @@ static void prepare_error_buf(const char *fmt, va_list args)
char *fmt1 = fmt_buf;
char *k;
char *p = error_buf;
char * const end = &error_buf[sizeof(error_buf)];
int what;
spin_lock(&error_lock);
strcpy(fmt1, fmt);
if (WARN_ON(strscpy(fmt_buf, fmt, sizeof(fmt_buf)) < 0)) {
strscpy(error_buf, "format string too long", end - error_buf);
goto out_unlock;
}
while ((k = is_there_reiserfs_struct(fmt1, &what)) != NULL) {
*k = 0;
p += vsprintf(p, fmt1, args);
p += vscnprintf(p, end - p, fmt1, args);
switch (what) {
case 'k':
sprintf_le_key(p, va_arg(args, struct reiserfs_key *));
p += scnprintf_le_key(p, end - p,
va_arg(args, struct reiserfs_key *));
break;
case 'K':
sprintf_cpu_key(p, va_arg(args, struct cpu_key *));
p += scnprintf_cpu_key(p, end - p,
va_arg(args, struct cpu_key *));
break;
case 'h':
sprintf_item_head(p, va_arg(args, struct item_head *));
p += scnprintf_item_head(p, end - p,
va_arg(args, struct item_head *));
break;
case 't':
sprintf_direntry(p,
va_arg(args,
struct reiserfs_dir_entry *));
p += scnprintf_direntry(p, end - p,
va_arg(args, struct reiserfs_dir_entry *));
break;
case 'y':
sprintf_disk_child(p,
va_arg(args, struct disk_child *));
p += scnprintf_disk_child(p, end - p,
va_arg(args, struct disk_child *));
break;
case 'z':
sprintf_block_head(p,
va_arg(args, struct buffer_head *));
p += scnprintf_block_head(p, end - p,
va_arg(args, struct buffer_head *));
break;
case 'b':
sprintf_buffer_head(p,
va_arg(args, struct buffer_head *));
p += scnprintf_buffer_head(p, end - p,
va_arg(args, struct buffer_head *));
break;
case 'a':
sprintf_de_head(p,
va_arg(args,
struct reiserfs_de_head *));
p += scnprintf_de_head(p, end - p,
va_arg(args, struct reiserfs_de_head *));
break;
}
p += strlen(p);
fmt1 = k + 2;
}
vsprintf(p, fmt1, args);
p += vscnprintf(p, end - p, fmt1, args);
out_unlock:
spin_unlock(&error_lock);
}