diff options
Diffstat (limited to 'udev-remove.c')
| -rw-r--r-- | udev-remove.c | 46 |
1 files changed, 38 insertions, 8 deletions
diff --git a/udev-remove.c b/udev-remove.c index 27ff5bc0a2..4f2cd479c0 100644 --- a/udev-remove.c +++ b/udev-remove.c @@ -65,6 +65,41 @@ static int delete_path(char *path) return 0; } +/** Remove all permissions on the device node, before + * unlinking it. This fixes a security issue. + * If the user created a hard-link to the device node, + * he can't use it any longer, because he lost permission + * to do so. + */ +static int secure_unlink(const char *filename) +{ + int retval; + + retval = chown(filename, 0, 0); + if (retval) { + dbg("chown(%s, 0, 0) failed with error '%s'", + filename, strerror(errno)); + /* We continue nevertheless. + * I think it's very unlikely for chown + * to fail here, if the file exists. + */ + } + retval = chmod(filename, 0000); + if (retval) { + dbg("chmod(%s, 0000) failed with error '%s'", + filename, strerror(errno)); + /* We continue nevertheless. */ + } + retval = unlink(filename); + if (errno == ENOENT) + retval = 0; + if (retval) { + dbg("unlink(%s) failed with error '%s'", + filename, strerror(errno)); + } + return retval; +} + static int delete_node(struct udevice *dev) { char filename[NAME_SIZE]; @@ -79,14 +114,9 @@ static int delete_node(struct udevice *dev) strfieldcat(filename, dev->name); info("removing device node '%s'", filename); - retval = unlink(filename); - if (errno == ENOENT) - retval = 0; - if (retval) { - dbg("unlink(%s) failed with error '%s'", - filename, strerror(errno)); + retval = secure_unlink(filename); + if (retval) return retval; - } /* remove partition nodes */ if (dev->partitions > 0) { @@ -94,7 +124,7 @@ static int delete_node(struct udevice *dev) for (i = 1; i <= dev->partitions; i++) { strfieldcpy(partitionname, filename); strintcat(partitionname, i); - unlink(partitionname); + secure_unlink(partitionname); } } |