| Message ID | 20211217150007.GB16611@kili (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | ac1e6bc146d45e15f0a5c0908338f918f6261388 |
| Headers | show |
| Series | ASoC: qdsp6: fix a use after free bug in open() | expand |
On 2021-12-17 4:00 PM, Dan Carpenter wrote: > This code frees "graph" and then dereferences to save the error code. > Save the error code first and then use gotos to unwind the allocation. > > Fixes: 59716aa3f976 ("ASoC: qdsp6: Fix an IS_ERR() vs NULL bug") > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> > --- > sound/soc/qcom/qdsp6/q6apm.c | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/sound/soc/qcom/qdsp6/q6apm.c b/sound/soc/qcom/qdsp6/q6apm.c > index 3e007d609a9b..f424d7aa389a 100644 > --- a/sound/soc/qcom/qdsp6/q6apm.c > +++ b/sound/soc/qcom/qdsp6/q6apm.c > @@ -615,7 +615,7 @@ struct q6apm_graph *q6apm_graph_open(struct device *dev, q6apm_cb cb, > graph = kzalloc(sizeof(*graph), GFP_KERNEL); > if (!graph) { > ret = -ENOMEM; > - goto err; > + goto put_ar_graph; > } > > graph->apm = apm; > @@ -631,13 +631,15 @@ struct q6apm_graph *q6apm_graph_open(struct device *dev, q6apm_cb cb, > > graph->port = gpr_alloc_port(apm->gdev, dev, graph_callback, graph); > if (IS_ERR(graph->port)) { > - kfree(graph); > ret = PTR_ERR(graph->port); > - goto err; > + goto free_graph; > } > > return graph; > -err: > + > +free_graph: > + kfree(graph); > +put_ar_graph: Hello Dan, The patch looks good! My only suggestion is a readability improvement, but I'm unaware of the convention chosen for qcom directory so you may choose to ignore it: Function q6apm_graph_open() has two separate return paths: a happy path ending in 'return graph' and an error path which eventually ends with 'return ERR_PTR(ret)'. Current goto label-naming convention suggests it's a happy path nonetheless. s/free_graph/err_alloc_port/ and s/put_ar_graph/err_alloc_graph/ tells reader upfront that they are in the error path. Regards, Czarek > kref_put(&ar_graph->refcount, q6apm_put_audioreach_graph); > return ERR_PTR(ret); > } >
On Fri, 17 Dec 2021 18:00:07 +0300, Dan Carpenter wrote: > This code frees "graph" and then dereferences to save the error code. > Save the error code first and then use gotos to unwind the allocation. > > Applied to https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git for-next Thanks! [1/1] ASoC: qdsp6: fix a use after free bug in open() commit: ac1e6bc146d45e15f0a5c0908338f918f6261388 All being well this means that it will be integrated into the linux-next tree (usually sometime in the next 24 hours) and sent to Linus during the next merge window (or sooner if it is a bug fix), however if problems are discovered then the patch may be dropped or reverted. You may get further e-mails resulting from automated or manual testing and review of the tree, please engage with people reporting problems and send followup patches addressing any issues that are reported if needed. If any updates are required or you are submitting further changes they should be sent as incremental updates against current git, existing patches will not be replaced. Please add any relevant lists and maintainers to the CCs when replying to this mail. Thanks, Mark
On Fri, Dec 17, 2021 at 04:13:48PM +0100, Cezary Rojewski wrote: > On 2021-12-17 4:00 PM, Dan Carpenter wrote: > > This code frees "graph" and then dereferences to save the error code. > > Save the error code first and then use gotos to unwind the allocation. > > > > Fixes: 59716aa3f976 ("ASoC: qdsp6: Fix an IS_ERR() vs NULL bug") > > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> > > --- > > sound/soc/qcom/qdsp6/q6apm.c | 10 ++++++---- > > 1 file changed, 6 insertions(+), 4 deletions(-) > > > > diff --git a/sound/soc/qcom/qdsp6/q6apm.c b/sound/soc/qcom/qdsp6/q6apm.c > > index 3e007d609a9b..f424d7aa389a 100644 > > --- a/sound/soc/qcom/qdsp6/q6apm.c > > +++ b/sound/soc/qcom/qdsp6/q6apm.c > > @@ -615,7 +615,7 @@ struct q6apm_graph *q6apm_graph_open(struct device *dev, q6apm_cb cb, > > graph = kzalloc(sizeof(*graph), GFP_KERNEL); > > if (!graph) { > > ret = -ENOMEM; > > - goto err; > > + goto put_ar_graph; > > } > > graph->apm = apm; > > @@ -631,13 +631,15 @@ struct q6apm_graph *q6apm_graph_open(struct device *dev, q6apm_cb cb, > > graph->port = gpr_alloc_port(apm->gdev, dev, graph_callback, graph); > > if (IS_ERR(graph->port)) { > > - kfree(graph); > > ret = PTR_ERR(graph->port); > > - goto err; > > + goto free_graph; > > } > > return graph; > > -err: > > + > > +free_graph: > > + kfree(graph); > > +put_ar_graph: > > Hello Dan, > > The patch looks good! My only suggestion is a readability improvement, but > I'm unaware of the convention chosen for qcom directory so you may choose to > ignore it: > > Function q6apm_graph_open() has two separate return paths: a happy path > ending in 'return graph' and an error path which eventually ends with > 'return ERR_PTR(ret)'. Current goto label-naming convention suggests it's a > happy path nonetheless. > > s/free_graph/err_alloc_port/ and s/put_ar_graph/err_alloc_graph/ tells > reader upfront that they are in the error path. > Generally when code is indented two tabs that's an error path. The relevant pattern is "Do error handling, not success handling". I guess the if (IS_ERR()) check means it's an error as well. regards, dan carpenter
diff --git a/sound/soc/qcom/qdsp6/q6apm.c b/sound/soc/qcom/qdsp6/q6apm.c index 3e007d609a9b..f424d7aa389a 100644 --- a/sound/soc/qcom/qdsp6/q6apm.c +++ b/sound/soc/qcom/qdsp6/q6apm.c @@ -615,7 +615,7 @@ struct q6apm_graph *q6apm_graph_open(struct device *dev, q6apm_cb cb, graph = kzalloc(sizeof(*graph), GFP_KERNEL); if (!graph) { ret = -ENOMEM; - goto err; + goto put_ar_graph; } graph->apm = apm; @@ -631,13 +631,15 @@ struct q6apm_graph *q6apm_graph_open(struct device *dev, q6apm_cb cb, graph->port = gpr_alloc_port(apm->gdev, dev, graph_callback, graph); if (IS_ERR(graph->port)) { - kfree(graph); ret = PTR_ERR(graph->port); - goto err; + goto free_graph; } return graph; -err: + +free_graph: + kfree(graph); +put_ar_graph: kref_put(&ar_graph->refcount, q6apm_put_audioreach_graph); return ERR_PTR(ret); }
This code frees "graph" and then dereferences to save the error code. Save the error code first and then use gotos to unwind the allocation. Fixes: 59716aa3f976 ("ASoC: qdsp6: Fix an IS_ERR() vs NULL bug") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> --- sound/soc/qcom/qdsp6/q6apm.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)