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author | Javier Martinez Canillas <javierm@redhat.com> | 2022-07-05 13:02:13 +0300 |
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committer | Javier Martinez Canillas <javierm@redhat.com> | 2022-07-15 11:25:01 +0300 |
commit | 94dc3471d1b2b58b3728558d0e3f264e9ce6ff59 (patch) | |
tree | a53cafb9d2d42ea459b7f4649711e4e3fc3e4ad3 /drivers | |
parent | 887ddf3251928dc39bfc58c5c62083d38a633c14 (diff) | |
download | linux-94dc3471d1b2b58b3728558d0e3f264e9ce6ff59.tar.xz |
drm: Use size_t type for len variable in drm_copy_field()
The strlen() function returns a size_t which is an unsigned int on 32-bit
arches and an unsigned long on 64-bit arches. But in the drm_copy_field()
function, the strlen() return value is assigned to an 'int len' variable.
Later, the len variable is passed as copy_from_user() third argument that
is an unsigned long parameter as well.
In theory, this can lead to an integer overflow via type conversion. Since
the assignment happens to a signed int lvalue instead of a size_t lvalue.
In practice though, that's unlikely since the values copied are set by DRM
drivers and not controlled by userspace. But using a size_t for len is the
correct thing to do anyways.
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Tested-by: Peter Robinson <pbrobinson@gmail.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220705100215.572498-2-javierm@redhat.com
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/gpu/drm/drm_ioctl.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c index 8faad23dc1d8..e1b9a03e619c 100644 --- a/drivers/gpu/drm/drm_ioctl.c +++ b/drivers/gpu/drm/drm_ioctl.c @@ -472,7 +472,7 @@ EXPORT_SYMBOL(drm_invalid_op); */ static int drm_copy_field(char __user *buf, size_t *buf_len, const char *value) { - int len; + size_t len; /* don't overflow userbuf */ len = strlen(value); |