| Message ID | 21282b66-9860-410a-83df-39c17fcf2f1b@kili.mountain (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 4d43acb145c363626d76f49febb4240c488cd1cf |
| Headers | show |
| Series | dmaengine: at_xdmac: fix potential Oops in at_xdmac_prep_interleaved() | expand |
On 5/15/23 11:32, Dan Carpenter wrote: > There are two place if the at_xdmac_interleaved_queue_desc() fails which > could lead to a NULL dereference where "first" is NULL and we call > list_add_tail(&first->desc_node, ...). In the first caller, the return > is not checked so add a check for that. In the next caller, the return > is checked but if it fails on the first iteration through the loop then > it will lead to a NULL pointer dereference. > > Fixes: 4e5385784e69 ("dmaengine: at_xdmac: handle numf > 1") > Fixes: 62b5cb757f1d ("dmaengine: at_xdmac: fix memory leak in interleaved mode") > Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org> Reviewed-by: Tudor Ambarus <tudor.ambarus@linaro.org> > --- > drivers/dma/at_xdmac.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c > index 7da6d9b6098e..c3b37168b21f 100644 > --- a/drivers/dma/at_xdmac.c > +++ b/drivers/dma/at_xdmac.c > @@ -1102,6 +1102,8 @@ at_xdmac_prep_interleaved(struct dma_chan *chan, > NULL, > src_addr, dst_addr, > xt, xt->sgl); > + if (!first) > + return NULL; > > /* Length of the block is (BLEN+1) microblocks. */ > for (i = 0; i < xt->numf - 1; i++) > @@ -1132,8 +1134,9 @@ at_xdmac_prep_interleaved(struct dma_chan *chan, > src_addr, dst_addr, > xt, chunk); > if (!desc) { > - list_splice_tail_init(&first->descs_list, > - &atchan->free_descs_list); > + if (first) > + list_splice_tail_init(&first->descs_list, > + &atchan->free_descs_list); > return NULL; > } >
On 15-05-23, 13:32, Dan Carpenter wrote: > There are two place if the at_xdmac_interleaved_queue_desc() fails which > could lead to a NULL dereference where "first" is NULL and we call > list_add_tail(&first->desc_node, ...). In the first caller, the return > is not checked so add a check for that. In the next caller, the return > is checked but if it fails on the first iteration through the loop then > it will lead to a NULL pointer dereference. Applied, thanks
diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c index 7da6d9b6098e..c3b37168b21f 100644 --- a/drivers/dma/at_xdmac.c +++ b/drivers/dma/at_xdmac.c @@ -1102,6 +1102,8 @@ at_xdmac_prep_interleaved(struct dma_chan *chan, NULL, src_addr, dst_addr, xt, xt->sgl); + if (!first) + return NULL; /* Length of the block is (BLEN+1) microblocks. */ for (i = 0; i < xt->numf - 1; i++) @@ -1132,8 +1134,9 @@ at_xdmac_prep_interleaved(struct dma_chan *chan, src_addr, dst_addr, xt, chunk); if (!desc) { - list_splice_tail_init(&first->descs_list, - &atchan->free_descs_list); + if (first) + list_splice_tail_init(&first->descs_list, + &atchan->free_descs_list); return NULL; }
There are two place if the at_xdmac_interleaved_queue_desc() fails which could lead to a NULL dereference where "first" is NULL and we call list_add_tail(&first->desc_node, ...). In the first caller, the return is not checked so add a check for that. In the next caller, the return is checked but if it fails on the first iteration through the loop then it will lead to a NULL pointer dereference. Fixes: 4e5385784e69 ("dmaengine: at_xdmac: handle numf > 1") Fixes: 62b5cb757f1d ("dmaengine: at_xdmac: fix memory leak in interleaved mode") Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org> --- drivers/dma/at_xdmac.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)