| Message ID | dea98f0b07e16de219d8741c1fefc7cb476cb482.1586681010.git.riteshh@linux.ibm.com |
|---|---|
| State | New |
| Headers | show |
| Series | [RFC,1/1] ext4: Fix overflow case for map.m_len in ext4_iomap_begin_* | expand |
On Sun 12-04-20 14:54:35, Ritesh Harjani wrote: > EXT4_MAX_LOGICAL_BLOCK - map.m_lblk + 1 in case when > map.m_lblk (offset) is 0 could overflow an unsigned int > and become 0. > > Fix this. > > Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com> > Reported-by: syzbot+77fa5bdb65cc39711820@syzkaller.appspotmail.com > Fixes: d3b6f23f7167 ("ext4: move ext4_fiemap to use iomap framework") The patch looks good to me. You can add: Reviewed-by: Jan Kara <jack@suse.cz> Honza > --- > fs/ext4/inode.c | 12 ++++++++++-- > 1 file changed, 10 insertions(+), 2 deletions(-) > > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > index e416096fc081..d630ec7a9c8e 100644 > --- a/fs/ext4/inode.c > +++ b/fs/ext4/inode.c > @@ -3424,6 +3424,7 @@ static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length, > int ret; > struct ext4_map_blocks map; > u8 blkbits = inode->i_blkbits; > + loff_t len; > > if ((offset >> blkbits) > EXT4_MAX_LOGICAL_BLOCK) > return -EINVAL; > @@ -3435,8 +3436,11 @@ static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length, > * Calculate the first and last logical blocks respectively. > */ > map.m_lblk = offset >> blkbits; > - map.m_len = min_t(loff_t, (offset + length - 1) >> blkbits, > + len = min_t(loff_t, (offset + length - 1) >> blkbits, > EXT4_MAX_LOGICAL_BLOCK) - map.m_lblk + 1; > + if (len > EXT4_MAX_LOGICAL_BLOCK) > + len = EXT4_MAX_LOGICAL_BLOCK; > + map.m_len = len; > > if (flags & IOMAP_WRITE) > ret = ext4_iomap_alloc(inode, &map, flags); > @@ -3524,6 +3528,7 @@ static int ext4_iomap_begin_report(struct inode *inode, loff_t offset, > bool delalloc = false; > struct ext4_map_blocks map; > u8 blkbits = inode->i_blkbits; > + loff_t len > > if ((offset >> blkbits) > EXT4_MAX_LOGICAL_BLOCK) > return -EINVAL; > @@ -3541,8 +3546,11 @@ static int ext4_iomap_begin_report(struct inode *inode, loff_t offset, > * Calculate the first and last logical block respectively. > */ > map.m_lblk = offset >> blkbits; > - map.m_len = min_t(loff_t, (offset + length - 1) >> blkbits, > + len = min_t(loff_t, (offset + length - 1) >> blkbits, > EXT4_MAX_LOGICAL_BLOCK) - map.m_lblk + 1; > + if (len > EXT4_MAX_LOGICAL_BLOCK) > + len = EXT4_MAX_LOGICAL_BLOCK; > + map.m_len = len; > > /* > * Fiemap callers may call for offset beyond s_bitmap_maxbytes. > -- > 2.21.0 >
Sorry Jan and others. Please ignore this patch. I will resend a proper one after making sure it is tested via syzbot. On 4/14/20 9:20 PM, Jan Kara wrote: > On Sun 12-04-20 14:54:35, Ritesh Harjani wrote: >> EXT4_MAX_LOGICAL_BLOCK - map.m_lblk + 1 in case when >> map.m_lblk (offset) is 0 could overflow an unsigned int >> and become 0. >> >> Fix this. >> >> Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com> >> Reported-by: syzbot+77fa5bdb65cc39711820@syzkaller.appspotmail.com >> Fixes: d3b6f23f7167 ("ext4: move ext4_fiemap to use iomap framework") > > The patch looks good to me. You can add: > > Reviewed-by: Jan Kara <jack@suse.cz> > > Honza > >> --- >> fs/ext4/inode.c | 12 ++++++++++-- >> 1 file changed, 10 insertions(+), 2 deletions(-) >> >> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c >> index e416096fc081..d630ec7a9c8e 100644 >> --- a/fs/ext4/inode.c >> +++ b/fs/ext4/inode.c >> @@ -3424,6 +3424,7 @@ static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length, >> int ret; >> struct ext4_map_blocks map; >> u8 blkbits = inode->i_blkbits; >> + loff_t len; >> >> if ((offset >> blkbits) > EXT4_MAX_LOGICAL_BLOCK) >> return -EINVAL; >> @@ -3435,8 +3436,11 @@ static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length, >> * Calculate the first and last logical blocks respectively. >> */ >> map.m_lblk = offset >> blkbits; >> - map.m_len = min_t(loff_t, (offset + length - 1) >> blkbits, >> + len = min_t(loff_t, (offset + length - 1) >> blkbits, >> EXT4_MAX_LOGICAL_BLOCK) - map.m_lblk + 1; >> + if (len > EXT4_MAX_LOGICAL_BLOCK) >> + len = EXT4_MAX_LOGICAL_BLOCK; >> + map.m_len = len; >> >> if (flags & IOMAP_WRITE) >> ret = ext4_iomap_alloc(inode, &map, flags); >> @@ -3524,6 +3528,7 @@ static int ext4_iomap_begin_report(struct inode *inode, loff_t offset, >> bool delalloc = false; >> struct ext4_map_blocks map; >> u8 blkbits = inode->i_blkbits; >> + loff_t len >> >> if ((offset >> blkbits) > EXT4_MAX_LOGICAL_BLOCK) >> return -EINVAL; >> @@ -3541,8 +3546,11 @@ static int ext4_iomap_begin_report(struct inode *inode, loff_t offset, >> * Calculate the first and last logical block respectively. >> */ >> map.m_lblk = offset >> blkbits; >> - map.m_len = min_t(loff_t, (offset + length - 1) >> blkbits, >> + len = min_t(loff_t, (offset + length - 1) >> blkbits, >> EXT4_MAX_LOGICAL_BLOCK) - map.m_lblk + 1; >> + if (len > EXT4_MAX_LOGICAL_BLOCK) >> + len = EXT4_MAX_LOGICAL_BLOCK; >> + map.m_len = len; >> >> /* >> * Fiemap callers may call for offset beyond s_bitmap_maxbytes. >> -- >> 2.21.0 >>
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index e416096fc081..d630ec7a9c8e 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3424,6 +3424,7 @@ static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length, int ret; struct ext4_map_blocks map; u8 blkbits = inode->i_blkbits; + loff_t len; if ((offset >> blkbits) > EXT4_MAX_LOGICAL_BLOCK) return -EINVAL; @@ -3435,8 +3436,11 @@ static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length, * Calculate the first and last logical blocks respectively. */ map.m_lblk = offset >> blkbits; - map.m_len = min_t(loff_t, (offset + length - 1) >> blkbits, + len = min_t(loff_t, (offset + length - 1) >> blkbits, EXT4_MAX_LOGICAL_BLOCK) - map.m_lblk + 1; + if (len > EXT4_MAX_LOGICAL_BLOCK) + len = EXT4_MAX_LOGICAL_BLOCK; + map.m_len = len; if (flags & IOMAP_WRITE) ret = ext4_iomap_alloc(inode, &map, flags); @@ -3524,6 +3528,7 @@ static int ext4_iomap_begin_report(struct inode *inode, loff_t offset, bool delalloc = false; struct ext4_map_blocks map; u8 blkbits = inode->i_blkbits; + loff_t len if ((offset >> blkbits) > EXT4_MAX_LOGICAL_BLOCK) return -EINVAL; @@ -3541,8 +3546,11 @@ static int ext4_iomap_begin_report(struct inode *inode, loff_t offset, * Calculate the first and last logical block respectively. */ map.m_lblk = offset >> blkbits; - map.m_len = min_t(loff_t, (offset + length - 1) >> blkbits, + len = min_t(loff_t, (offset + length - 1) >> blkbits, EXT4_MAX_LOGICAL_BLOCK) - map.m_lblk + 1; + if (len > EXT4_MAX_LOGICAL_BLOCK) + len = EXT4_MAX_LOGICAL_BLOCK; + map.m_len = len; /* * Fiemap callers may call for offset beyond s_bitmap_maxbytes.
EXT4_MAX_LOGICAL_BLOCK - map.m_lblk + 1 in case when map.m_lblk (offset) is 0 could overflow an unsigned int and become 0. Fix this. Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com> Reported-by: syzbot+77fa5bdb65cc39711820@syzkaller.appspotmail.com Fixes: d3b6f23f7167 ("ext4: move ext4_fiemap to use iomap framework") --- fs/ext4/inode.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)