* [PATCH] erofs: fix buffer copy overflow of ztailpacking feature
@ 2022-05-12 11:58 ` Gao Xiang
0 siblings, 0 replies; 8+ messages in thread
From: Gao Xiang @ 2022-05-12 11:58 UTC (permalink / raw)
To: linux-erofs, Chao Yu; +Cc: LKML, Yue Hu, Gao Xiang
I got some KASAN report as below:
[ 46.959738] ==================================================================
[ 46.960430] BUG: KASAN: use-after-free in z_erofs_shifted_transform+0x2bd/0x370
[ 46.960430] Read of size 4074 at addr ffff8880300c2f8e by task fssum/188
...
[ 46.960430] Call Trace:
[ 46.960430] <TASK>
[ 46.960430] dump_stack_lvl+0x41/0x5e
[ 46.960430] print_report.cold+0xb2/0x6b7
[ 46.960430] ? z_erofs_shifted_transform+0x2bd/0x370
[ 46.960430] kasan_report+0x8a/0x140
[ 46.960430] ? z_erofs_shifted_transform+0x2bd/0x370
[ 46.960430] kasan_check_range+0x14d/0x1d0
[ 46.960430] memcpy+0x20/0x60
[ 46.960430] z_erofs_shifted_transform+0x2bd/0x370
[ 46.960430] z_erofs_decompress_pcluster+0xaae/0x1080
The root cause is that the tail pcluster won't be a complete filesystem
block anymore. So if ztailpacking is used, the second part of an
uncompresed tail pcluster may not be ``rq->pageofs_out``.
Fixes: ab749badf9f4 ("erofs: support unaligned data decompression")
Fixes: cecf864d3d76 ("erofs: support inline data decompression")
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
---
fs/erofs/decompressor.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
index 0f445f7e1df8..6dca1900c733 100644
--- a/fs/erofs/decompressor.c
+++ b/fs/erofs/decompressor.c
@@ -320,6 +320,7 @@ static int z_erofs_shifted_transform(struct z_erofs_decompress_req *rq,
PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;
const unsigned int righthalf = min_t(unsigned int, rq->outputsize,
PAGE_SIZE - rq->pageofs_out);
+ const unsigned int lefthalf = rq->outputsize - righthalf;
unsigned char *src, *dst;
if (nrpages_out > 2) {
@@ -342,10 +343,10 @@ static int z_erofs_shifted_transform(struct z_erofs_decompress_req *rq,
if (nrpages_out == 2) {
DBG_BUGON(!rq->out[1]);
if (rq->out[1] == *rq->in) {
- memmove(src, src + righthalf, rq->pageofs_out);
+ memmove(src, src + righthalf, lefthalf);
} else {
dst = kmap_atomic(rq->out[1]);
- memcpy(dst, src + righthalf, rq->pageofs_out);
+ memcpy(dst, src + righthalf, lefthalf);
kunmap_atomic(dst);
}
}
--
2.24.4
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH] erofs: fix buffer copy overflow of ztailpacking feature
@ 2022-05-12 11:58 ` Gao Xiang
0 siblings, 0 replies; 8+ messages in thread
From: Gao Xiang @ 2022-05-12 11:58 UTC (permalink / raw)
To: linux-erofs, Chao Yu; +Cc: Gao Xiang, Yue Hu, LKML
I got some KASAN report as below:
[ 46.959738] ==================================================================
[ 46.960430] BUG: KASAN: use-after-free in z_erofs_shifted_transform+0x2bd/0x370
[ 46.960430] Read of size 4074 at addr ffff8880300c2f8e by task fssum/188
...
[ 46.960430] Call Trace:
[ 46.960430] <TASK>
[ 46.960430] dump_stack_lvl+0x41/0x5e
[ 46.960430] print_report.cold+0xb2/0x6b7
[ 46.960430] ? z_erofs_shifted_transform+0x2bd/0x370
[ 46.960430] kasan_report+0x8a/0x140
[ 46.960430] ? z_erofs_shifted_transform+0x2bd/0x370
[ 46.960430] kasan_check_range+0x14d/0x1d0
[ 46.960430] memcpy+0x20/0x60
[ 46.960430] z_erofs_shifted_transform+0x2bd/0x370
[ 46.960430] z_erofs_decompress_pcluster+0xaae/0x1080
The root cause is that the tail pcluster won't be a complete filesystem
block anymore. So if ztailpacking is used, the second part of an
uncompresed tail pcluster may not be ``rq->pageofs_out``.
Fixes: ab749badf9f4 ("erofs: support unaligned data decompression")
Fixes: cecf864d3d76 ("erofs: support inline data decompression")
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
---
fs/erofs/decompressor.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
index 0f445f7e1df8..6dca1900c733 100644
--- a/fs/erofs/decompressor.c
+++ b/fs/erofs/decompressor.c
@@ -320,6 +320,7 @@ static int z_erofs_shifted_transform(struct z_erofs_decompress_req *rq,
PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;
const unsigned int righthalf = min_t(unsigned int, rq->outputsize,
PAGE_SIZE - rq->pageofs_out);
+ const unsigned int lefthalf = rq->outputsize - righthalf;
unsigned char *src, *dst;
if (nrpages_out > 2) {
@@ -342,10 +343,10 @@ static int z_erofs_shifted_transform(struct z_erofs_decompress_req *rq,
if (nrpages_out == 2) {
DBG_BUGON(!rq->out[1]);
if (rq->out[1] == *rq->in) {
- memmove(src, src + righthalf, rq->pageofs_out);
+ memmove(src, src + righthalf, lefthalf);
} else {
dst = kmap_atomic(rq->out[1]);
- memcpy(dst, src + righthalf, rq->pageofs_out);
+ memcpy(dst, src + righthalf, lefthalf);
kunmap_atomic(dst);
}
}
--
2.24.4
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH] erofs: fix buffer copy overflow of ztailpacking feature
2022-05-12 11:58 ` Gao Xiang
@ 2022-05-13 6:14 ` Yue Hu
-1 siblings, 0 replies; 8+ messages in thread
From: Yue Hu @ 2022-05-13 6:14 UTC (permalink / raw)
To: Gao Xiang; +Cc: LKML, zhangwen, Yue Hu, huyue2, linux-erofs
On Thu, 12 May 2022 19:58:33 +0800
Gao Xiang <hsiangkao@linux.alibaba.com> wrote:
> I got some KASAN report as below:
>
> [ 46.959738] ==================================================================
> [ 46.960430] BUG: KASAN: use-after-free in z_erofs_shifted_transform+0x2bd/0x370
> [ 46.960430] Read of size 4074 at addr ffff8880300c2f8e by task fssum/188
> ...
> [ 46.960430] Call Trace:
> [ 46.960430] <TASK>
> [ 46.960430] dump_stack_lvl+0x41/0x5e
> [ 46.960430] print_report.cold+0xb2/0x6b7
> [ 46.960430] ? z_erofs_shifted_transform+0x2bd/0x370
> [ 46.960430] kasan_report+0x8a/0x140
> [ 46.960430] ? z_erofs_shifted_transform+0x2bd/0x370
> [ 46.960430] kasan_check_range+0x14d/0x1d0
> [ 46.960430] memcpy+0x20/0x60
> [ 46.960430] z_erofs_shifted_transform+0x2bd/0x370
> [ 46.960430] z_erofs_decompress_pcluster+0xaae/0x1080
>
> The root cause is that the tail pcluster won't be a complete filesystem
> block anymore. So if ztailpacking is used, the second part of an
> uncompresed tail pcluster may not be ``rq->pageofs_out``.
Yeah, since we have a 'pageofs_in' to the 'src' for ztailpacking.
Reviewed-by: Yue Hu <huyue2@coolpad.com>
>
> Fixes: ab749badf9f4 ("erofs: support unaligned data decompression")
> Fixes: cecf864d3d76 ("erofs: support inline data decompression")
> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
> ---
> fs/erofs/decompressor.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
> index 0f445f7e1df8..6dca1900c733 100644
> --- a/fs/erofs/decompressor.c
> +++ b/fs/erofs/decompressor.c
> @@ -320,6 +320,7 @@ static int z_erofs_shifted_transform(struct z_erofs_decompress_req *rq,
> PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;
> const unsigned int righthalf = min_t(unsigned int, rq->outputsize,
> PAGE_SIZE - rq->pageofs_out);
> + const unsigned int lefthalf = rq->outputsize - righthalf;
> unsigned char *src, *dst;
>
> if (nrpages_out > 2) {
> @@ -342,10 +343,10 @@ static int z_erofs_shifted_transform(struct z_erofs_decompress_req *rq,
> if (nrpages_out == 2) {
> DBG_BUGON(!rq->out[1]);
> if (rq->out[1] == *rq->in) {
> - memmove(src, src + righthalf, rq->pageofs_out);
> + memmove(src, src + righthalf, lefthalf);
> } else {
> dst = kmap_atomic(rq->out[1]);
> - memcpy(dst, src + righthalf, rq->pageofs_out);
> + memcpy(dst, src + righthalf, lefthalf);
> kunmap_atomic(dst);
> }
> }
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] erofs: fix buffer copy overflow of ztailpacking feature
@ 2022-05-13 6:14 ` Yue Hu
0 siblings, 0 replies; 8+ messages in thread
From: Yue Hu @ 2022-05-13 6:14 UTC (permalink / raw)
To: Gao Xiang; +Cc: linux-erofs, Chao Yu, Yue Hu, LKML, zhangwen, huyue2
On Thu, 12 May 2022 19:58:33 +0800
Gao Xiang <hsiangkao@linux.alibaba.com> wrote:
> I got some KASAN report as below:
>
> [ 46.959738] ==================================================================
> [ 46.960430] BUG: KASAN: use-after-free in z_erofs_shifted_transform+0x2bd/0x370
> [ 46.960430] Read of size 4074 at addr ffff8880300c2f8e by task fssum/188
> ...
> [ 46.960430] Call Trace:
> [ 46.960430] <TASK>
> [ 46.960430] dump_stack_lvl+0x41/0x5e
> [ 46.960430] print_report.cold+0xb2/0x6b7
> [ 46.960430] ? z_erofs_shifted_transform+0x2bd/0x370
> [ 46.960430] kasan_report+0x8a/0x140
> [ 46.960430] ? z_erofs_shifted_transform+0x2bd/0x370
> [ 46.960430] kasan_check_range+0x14d/0x1d0
> [ 46.960430] memcpy+0x20/0x60
> [ 46.960430] z_erofs_shifted_transform+0x2bd/0x370
> [ 46.960430] z_erofs_decompress_pcluster+0xaae/0x1080
>
> The root cause is that the tail pcluster won't be a complete filesystem
> block anymore. So if ztailpacking is used, the second part of an
> uncompresed tail pcluster may not be ``rq->pageofs_out``.
Yeah, since we have a 'pageofs_in' to the 'src' for ztailpacking.
Reviewed-by: Yue Hu <huyue2@coolpad.com>
>
> Fixes: ab749badf9f4 ("erofs: support unaligned data decompression")
> Fixes: cecf864d3d76 ("erofs: support inline data decompression")
> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
> ---
> fs/erofs/decompressor.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
> index 0f445f7e1df8..6dca1900c733 100644
> --- a/fs/erofs/decompressor.c
> +++ b/fs/erofs/decompressor.c
> @@ -320,6 +320,7 @@ static int z_erofs_shifted_transform(struct z_erofs_decompress_req *rq,
> PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;
> const unsigned int righthalf = min_t(unsigned int, rq->outputsize,
> PAGE_SIZE - rq->pageofs_out);
> + const unsigned int lefthalf = rq->outputsize - righthalf;
> unsigned char *src, *dst;
>
> if (nrpages_out > 2) {
> @@ -342,10 +343,10 @@ static int z_erofs_shifted_transform(struct z_erofs_decompress_req *rq,
> if (nrpages_out == 2) {
> DBG_BUGON(!rq->out[1]);
> if (rq->out[1] == *rq->in) {
> - memmove(src, src + righthalf, rq->pageofs_out);
> + memmove(src, src + righthalf, lefthalf);
> } else {
> dst = kmap_atomic(rq->out[1]);
> - memcpy(dst, src + righthalf, rq->pageofs_out);
> + memcpy(dst, src + righthalf, lefthalf);
> kunmap_atomic(dst);
> }
> }
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] erofs: fix buffer copy overflow of ztailpacking feature
2022-05-12 11:58 ` Gao Xiang
@ 2022-05-17 15:10 ` Chao Yu
-1 siblings, 0 replies; 8+ messages in thread
From: Chao Yu @ 2022-05-17 15:10 UTC (permalink / raw)
To: Gao Xiang, linux-erofs; +Cc: LKML, Yue Hu
On 2022/5/12 19:58, Gao Xiang wrote:
> I got some KASAN report as below:
>
> [ 46.959738] ==================================================================
> [ 46.960430] BUG: KASAN: use-after-free in z_erofs_shifted_transform+0x2bd/0x370
> [ 46.960430] Read of size 4074 at addr ffff8880300c2f8e by task fssum/188
> ...
> [ 46.960430] Call Trace:
> [ 46.960430] <TASK>
> [ 46.960430] dump_stack_lvl+0x41/0x5e
> [ 46.960430] print_report.cold+0xb2/0x6b7
> [ 46.960430] ? z_erofs_shifted_transform+0x2bd/0x370
> [ 46.960430] kasan_report+0x8a/0x140
> [ 46.960430] ? z_erofs_shifted_transform+0x2bd/0x370
> [ 46.960430] kasan_check_range+0x14d/0x1d0
> [ 46.960430] memcpy+0x20/0x60
> [ 46.960430] z_erofs_shifted_transform+0x2bd/0x370
> [ 46.960430] z_erofs_decompress_pcluster+0xaae/0x1080
>
> The root cause is that the tail pcluster won't be a complete filesystem
> block anymore. So if ztailpacking is used, the second part of an
> uncompresed tail pcluster may not be ``rq->pageofs_out``.
uncompressed
>
> Fixes: ab749badf9f4 ("erofs: support unaligned data decompression")
> Fixes: cecf864d3d76 ("erofs: support inline data decompression")
> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Thanks,
> ---
> fs/erofs/decompressor.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
> index 0f445f7e1df8..6dca1900c733 100644
> --- a/fs/erofs/decompressor.c
> +++ b/fs/erofs/decompressor.c
> @@ -320,6 +320,7 @@ static int z_erofs_shifted_transform(struct z_erofs_decompress_req *rq,
> PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;
> const unsigned int righthalf = min_t(unsigned int, rq->outputsize,
> PAGE_SIZE - rq->pageofs_out);
> + const unsigned int lefthalf = rq->outputsize - righthalf;
> unsigned char *src, *dst;
>
> if (nrpages_out > 2) {
> @@ -342,10 +343,10 @@ static int z_erofs_shifted_transform(struct z_erofs_decompress_req *rq,
> if (nrpages_out == 2) {
> DBG_BUGON(!rq->out[1]);
> if (rq->out[1] == *rq->in) {
> - memmove(src, src + righthalf, rq->pageofs_out);
> + memmove(src, src + righthalf, lefthalf);
> } else {
> dst = kmap_atomic(rq->out[1]);
> - memcpy(dst, src + righthalf, rq->pageofs_out);
> + memcpy(dst, src + righthalf, lefthalf);
> kunmap_atomic(dst);
> }
> }
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] erofs: fix buffer copy overflow of ztailpacking feature
@ 2022-05-17 15:10 ` Chao Yu
0 siblings, 0 replies; 8+ messages in thread
From: Chao Yu @ 2022-05-17 15:10 UTC (permalink / raw)
To: Gao Xiang, linux-erofs; +Cc: Yue Hu, LKML
On 2022/5/12 19:58, Gao Xiang wrote:
> I got some KASAN report as below:
>
> [ 46.959738] ==================================================================
> [ 46.960430] BUG: KASAN: use-after-free in z_erofs_shifted_transform+0x2bd/0x370
> [ 46.960430] Read of size 4074 at addr ffff8880300c2f8e by task fssum/188
> ...
> [ 46.960430] Call Trace:
> [ 46.960430] <TASK>
> [ 46.960430] dump_stack_lvl+0x41/0x5e
> [ 46.960430] print_report.cold+0xb2/0x6b7
> [ 46.960430] ? z_erofs_shifted_transform+0x2bd/0x370
> [ 46.960430] kasan_report+0x8a/0x140
> [ 46.960430] ? z_erofs_shifted_transform+0x2bd/0x370
> [ 46.960430] kasan_check_range+0x14d/0x1d0
> [ 46.960430] memcpy+0x20/0x60
> [ 46.960430] z_erofs_shifted_transform+0x2bd/0x370
> [ 46.960430] z_erofs_decompress_pcluster+0xaae/0x1080
>
> The root cause is that the tail pcluster won't be a complete filesystem
> block anymore. So if ztailpacking is used, the second part of an
> uncompresed tail pcluster may not be ``rq->pageofs_out``.
uncompressed
>
> Fixes: ab749badf9f4 ("erofs: support unaligned data decompression")
> Fixes: cecf864d3d76 ("erofs: support inline data decompression")
> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Thanks,
> ---
> fs/erofs/decompressor.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
> index 0f445f7e1df8..6dca1900c733 100644
> --- a/fs/erofs/decompressor.c
> +++ b/fs/erofs/decompressor.c
> @@ -320,6 +320,7 @@ static int z_erofs_shifted_transform(struct z_erofs_decompress_req *rq,
> PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;
> const unsigned int righthalf = min_t(unsigned int, rq->outputsize,
> PAGE_SIZE - rq->pageofs_out);
> + const unsigned int lefthalf = rq->outputsize - righthalf;
> unsigned char *src, *dst;
>
> if (nrpages_out > 2) {
> @@ -342,10 +343,10 @@ static int z_erofs_shifted_transform(struct z_erofs_decompress_req *rq,
> if (nrpages_out == 2) {
> DBG_BUGON(!rq->out[1]);
> if (rq->out[1] == *rq->in) {
> - memmove(src, src + righthalf, rq->pageofs_out);
> + memmove(src, src + righthalf, lefthalf);
> } else {
> dst = kmap_atomic(rq->out[1]);
> - memcpy(dst, src + righthalf, rq->pageofs_out);
> + memcpy(dst, src + righthalf, lefthalf);
> kunmap_atomic(dst);
> }
> }
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] erofs: fix buffer copy overflow of ztailpacking feature
2022-05-17 15:10 ` Chao Yu
@ 2022-05-18 6:49 ` Gao Xiang
-1 siblings, 0 replies; 8+ messages in thread
From: Gao Xiang @ 2022-05-18 6:49 UTC (permalink / raw)
To: Chao Yu; +Cc: linux-erofs, LKML, Yue Hu
On Tue, May 17, 2022 at 11:10:15PM +0800, Chao Yu wrote:
> On 2022/5/12 19:58, Gao Xiang wrote:
> > I got some KASAN report as below:
> >
> > [ 46.959738] ==================================================================
> > [ 46.960430] BUG: KASAN: use-after-free in z_erofs_shifted_transform+0x2bd/0x370
> > [ 46.960430] Read of size 4074 at addr ffff8880300c2f8e by task fssum/188
> > ...
> > [ 46.960430] Call Trace:
> > [ 46.960430] <TASK>
> > [ 46.960430] dump_stack_lvl+0x41/0x5e
> > [ 46.960430] print_report.cold+0xb2/0x6b7
> > [ 46.960430] ? z_erofs_shifted_transform+0x2bd/0x370
> > [ 46.960430] kasan_report+0x8a/0x140
> > [ 46.960430] ? z_erofs_shifted_transform+0x2bd/0x370
> > [ 46.960430] kasan_check_range+0x14d/0x1d0
> > [ 46.960430] memcpy+0x20/0x60
> > [ 46.960430] z_erofs_shifted_transform+0x2bd/0x370
> > [ 46.960430] z_erofs_decompress_pcluster+0xaae/0x1080
> >
> > The root cause is that the tail pcluster won't be a complete filesystem
> > block anymore. So if ztailpacking is used, the second part of an
> > uncompresed tail pcluster may not be ``rq->pageofs_out``.
>
> uncompressed
Fixed, thanks!
Thanks,
Gao Xiang
>
> >
> > Fixes: ab749badf9f4 ("erofs: support unaligned data decompression")
> > Fixes: cecf864d3d76 ("erofs: support inline data decompression")
> > Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
>
> Reviewed-by: Chao Yu <chao@kernel.org>
>
> Thanks,
>
> > ---
> > fs/erofs/decompressor.c | 5 +++--
> > 1 file changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
> > index 0f445f7e1df8..6dca1900c733 100644
> > --- a/fs/erofs/decompressor.c
> > +++ b/fs/erofs/decompressor.c
> > @@ -320,6 +320,7 @@ static int z_erofs_shifted_transform(struct z_erofs_decompress_req *rq,
> > PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;
> > const unsigned int righthalf = min_t(unsigned int, rq->outputsize,
> > PAGE_SIZE - rq->pageofs_out);
> > + const unsigned int lefthalf = rq->outputsize - righthalf;
> > unsigned char *src, *dst;
> > if (nrpages_out > 2) {
> > @@ -342,10 +343,10 @@ static int z_erofs_shifted_transform(struct z_erofs_decompress_req *rq,
> > if (nrpages_out == 2) {
> > DBG_BUGON(!rq->out[1]);
> > if (rq->out[1] == *rq->in) {
> > - memmove(src, src + righthalf, rq->pageofs_out);
> > + memmove(src, src + righthalf, lefthalf);
> > } else {
> > dst = kmap_atomic(rq->out[1]);
> > - memcpy(dst, src + righthalf, rq->pageofs_out);
> > + memcpy(dst, src + righthalf, lefthalf);
> > kunmap_atomic(dst);
> > }
> > }
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] erofs: fix buffer copy overflow of ztailpacking feature
@ 2022-05-18 6:49 ` Gao Xiang
0 siblings, 0 replies; 8+ messages in thread
From: Gao Xiang @ 2022-05-18 6:49 UTC (permalink / raw)
To: Chao Yu; +Cc: Yue Hu, linux-erofs, LKML
On Tue, May 17, 2022 at 11:10:15PM +0800, Chao Yu wrote:
> On 2022/5/12 19:58, Gao Xiang wrote:
> > I got some KASAN report as below:
> >
> > [ 46.959738] ==================================================================
> > [ 46.960430] BUG: KASAN: use-after-free in z_erofs_shifted_transform+0x2bd/0x370
> > [ 46.960430] Read of size 4074 at addr ffff8880300c2f8e by task fssum/188
> > ...
> > [ 46.960430] Call Trace:
> > [ 46.960430] <TASK>
> > [ 46.960430] dump_stack_lvl+0x41/0x5e
> > [ 46.960430] print_report.cold+0xb2/0x6b7
> > [ 46.960430] ? z_erofs_shifted_transform+0x2bd/0x370
> > [ 46.960430] kasan_report+0x8a/0x140
> > [ 46.960430] ? z_erofs_shifted_transform+0x2bd/0x370
> > [ 46.960430] kasan_check_range+0x14d/0x1d0
> > [ 46.960430] memcpy+0x20/0x60
> > [ 46.960430] z_erofs_shifted_transform+0x2bd/0x370
> > [ 46.960430] z_erofs_decompress_pcluster+0xaae/0x1080
> >
> > The root cause is that the tail pcluster won't be a complete filesystem
> > block anymore. So if ztailpacking is used, the second part of an
> > uncompresed tail pcluster may not be ``rq->pageofs_out``.
>
> uncompressed
Fixed, thanks!
Thanks,
Gao Xiang
>
> >
> > Fixes: ab749badf9f4 ("erofs: support unaligned data decompression")
> > Fixes: cecf864d3d76 ("erofs: support inline data decompression")
> > Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
>
> Reviewed-by: Chao Yu <chao@kernel.org>
>
> Thanks,
>
> > ---
> > fs/erofs/decompressor.c | 5 +++--
> > 1 file changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
> > index 0f445f7e1df8..6dca1900c733 100644
> > --- a/fs/erofs/decompressor.c
> > +++ b/fs/erofs/decompressor.c
> > @@ -320,6 +320,7 @@ static int z_erofs_shifted_transform(struct z_erofs_decompress_req *rq,
> > PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;
> > const unsigned int righthalf = min_t(unsigned int, rq->outputsize,
> > PAGE_SIZE - rq->pageofs_out);
> > + const unsigned int lefthalf = rq->outputsize - righthalf;
> > unsigned char *src, *dst;
> > if (nrpages_out > 2) {
> > @@ -342,10 +343,10 @@ static int z_erofs_shifted_transform(struct z_erofs_decompress_req *rq,
> > if (nrpages_out == 2) {
> > DBG_BUGON(!rq->out[1]);
> > if (rq->out[1] == *rq->in) {
> > - memmove(src, src + righthalf, rq->pageofs_out);
> > + memmove(src, src + righthalf, lefthalf);
> > } else {
> > dst = kmap_atomic(rq->out[1]);
> > - memcpy(dst, src + righthalf, rq->pageofs_out);
> > + memcpy(dst, src + righthalf, lefthalf);
> > kunmap_atomic(dst);
> > }
> > }
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2022-05-18 6:49 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-05-12 11:58 [PATCH] erofs: fix buffer copy overflow of ztailpacking feature Gao Xiang
2022-05-12 11:58 ` Gao Xiang
2022-05-13 6:14 ` Yue Hu
2022-05-13 6:14 ` Yue Hu
2022-05-17 15:10 ` Chao Yu
2022-05-17 15:10 ` Chao Yu
2022-05-18 6:49 ` Gao Xiang
2022-05-18 6:49 ` Gao Xiang
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