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| author | Dan Carpenter <dan.carpenter@oracle.com> | 2022-05-06 09:55:15 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-05-19 19:28:37 +0200 |
| commit | 185b29c6151cf3a5c387ca5904c51c6af3292a0c (patch) | |
| tree | d97d6e083194e19965af8a225b63ea69e8357f51 /lib/test_firmware.c | |
| parent | 1f7ff11ca68f464b6a9a71b8fbe9e5219e7cac57 (diff) | |
| download | lwn-185b29c6151cf3a5c387ca5904c51c6af3292a0c.tar.gz lwn-185b29c6151cf3a5c387ca5904c51c6af3292a0c.zip | |
test_firmware: fix end of loop test in upload_read_show()
If a list_for_each_entry() loop exits without hitting a break statement
then the iterator points to invalid memory. So in this code the
"tst->name" dereference is an out bounds read. It's an offset from the
&test_upload_list pointer and it will likely work fine most of the time
but it's not correct.
One alternative is to fix this this by changing the test to:
if (list_entry_is_head(tst, &test_upload_list, node)) {
But the simpler, trendy new way is just create a new variable and test
for NULL.
Fixes: a31ad463b72d ("test_firmware: Add test support for firmware upload")
Reviewed-by: Russ Weight <russell.h.weight@intel.com>
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/YnTGU3UJOIA09I7e@kili
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'lib/test_firmware.c')
| -rw-r--r-- | lib/test_firmware.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/lib/test_firmware.c b/lib/test_firmware.c index 76115c1a2629..c82b65947ce6 100644 --- a/lib/test_firmware.c +++ b/lib/test_firmware.c @@ -1392,7 +1392,8 @@ static ssize_t upload_read_show(struct device *dev, struct device_attribute *attr, char *buf) { - struct test_firmware_upload *tst; + struct test_firmware_upload *tst = NULL; + struct test_firmware_upload *tst_iter; int ret = -EINVAL; if (!test_fw_config->upload_name) { @@ -1401,11 +1402,13 @@ static ssize_t upload_read_show(struct device *dev, } mutex_lock(&test_fw_mutex); - list_for_each_entry(tst, &test_upload_list, node) - if (tst->name == test_fw_config->upload_name) + list_for_each_entry(tst_iter, &test_upload_list, node) + if (tst_iter->name == test_fw_config->upload_name) { + tst = tst_iter; break; + } - if (tst->name != test_fw_config->upload_name) { + if (!tst) { pr_err("Firmware name not found: %s\n", test_fw_config->upload_name); goto out; |