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| author | Gui-Dong Han <hanguidong02@gmail.com> | 2026-03-23 11:58:44 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-04-02 17:15:23 +0300 |
| commit | 31de83980d3764d784f79ff1bc93c42b324f4013 (patch) | |
| tree | 52e36dd88ec09d7d5a715130b2f86cd81d3e455a | |
| parent | 56e3ee721b33bdc4ce0765d370983aa4384f8a59 (diff) | |
| download | linux-31de83980d3764d784f79ff1bc93c42b324f4013.tar.xz | |
debugfs: check for NULL pointer in debugfs_create_str()
Passing a NULL pointer to debugfs_create_str() leads to a NULL pointer
dereference when the debugfs file is read. Following upstream
discussions, forbid the creation of debugfs string files with NULL
pointers. Add a WARN_ON() to expose offending callers and return early.
Fixes: 9af0440ec86e ("debugfs: Implement debugfs_create_str()")
Reported-by: yangshiguang <yangshiguang@xiaomi.com>
Closes: https://lore.kernel.org/lkml/2025122221-gag-malt-75ba@gregkh/
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Gui-Dong Han <hanguidong02@gmail.com>
Link: https://patch.msgid.link/20260323085930.88894-2-hanguidong02@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | fs/debugfs/file.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c index 3376ab6a519d..a941d73251b0 100644 --- a/fs/debugfs/file.c +++ b/fs/debugfs/file.c @@ -1127,7 +1127,7 @@ static const struct file_operations fops_str_wo = { * directory dentry if set. If this parameter is %NULL, then the * file will be created in the root of the debugfs filesystem. * @value: a pointer to the variable that the file should read to and write - * from. + * from. This pointer and the string it points to must not be %NULL. * * This function creates a file in debugfs with the given name that * contains the value of the variable @value. If the @mode variable is so @@ -1136,6 +1136,9 @@ static const struct file_operations fops_str_wo = { void debugfs_create_str(const char *name, umode_t mode, struct dentry *parent, char **value) { + if (WARN_ON(!value || !*value)) + return; + debugfs_create_mode_unsafe(name, mode, parent, value, &fops_str, &fops_str_ro, &fops_str_wo); } |