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authorLinus Torvalds <torvalds@linux-foundation.org>2017-07-05 13:13:32 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-07-05 13:13:32 -0700
commit3bad2f1c676581d01e7645eb03e9b27e28b0a92e (patch)
tree7e946eb2c7dab8c08e473ee1249be9a814728158 /fs/fcntl.c
parentb4b8cbf679c4866a523a35d1454884a31bd5d8dc (diff)
parent8c6657cb50cb037ff58b3f6a547c6569568f3527 (diff)
Merge branch 'work.misc-set_fs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull misc user access cleanups from Al Viro: "The first pile is assorted getting rid of cargo-culted access_ok(), cargo-culted set_fs() and field-by-field copyouts. The same description applies to a lot of stuff in other branches - this is just the stuff that didn't fit into a more specific topical branch" * 'work.misc-set_fs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: Switch flock copyin/copyout primitives to copy_{from,to}_user() fs/fcntl: return -ESRCH in f_setown when pid/pgid can't be found fs/fcntl: f_setown, avoid undefined behaviour fs/fcntl: f_setown, allow returning error lpfc debugfs: get rid of pointless access_ok() adb: get rid of pointless access_ok() isdn: get rid of pointless access_ok() compat statfs: switch to copy_to_user() fs/locks: don't mess with the address limit in compat_fcntl64 nfsd_readlink(): switch to vfs_get_link() drbd: ->sendpage() never needed set_fs() fs/locks: pass kernel struct flock to fcntl_getlk/setlk fs: locks: Fix some troubles at kernel-doc comments
Diffstat (limited to 'fs/fcntl.c')
-rw-r--r--fs/fcntl.c231
1 files changed, 138 insertions, 93 deletions
diff --git a/fs/fcntl.c b/fs/fcntl.c
index ed051f825bad..b6bd89628025 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -109,20 +109,34 @@ void __f_setown(struct file *filp, struct pid *pid, enum pid_type type,
}
EXPORT_SYMBOL(__f_setown);
-void f_setown(struct file *filp, unsigned long arg, int force)
+int f_setown(struct file *filp, unsigned long arg, int force)
{
enum pid_type type;
- struct pid *pid;
- int who = arg;
+ struct pid *pid = NULL;
+ int who = arg, ret = 0;
+
type = PIDTYPE_PID;
if (who < 0) {
+ /* avoid overflow below */
+ if (who == INT_MIN)
+ return -EINVAL;
+
type = PIDTYPE_PGID;
who = -who;
}
+
rcu_read_lock();
- pid = find_vpid(who);
- __f_setown(filp, pid, type, force);
+ if (who) {
+ pid = find_vpid(who);
+ if (!pid)
+ ret = -ESRCH;
+ }
+
+ if (!ret)
+ __f_setown(filp, pid, type, force);
rcu_read_unlock();
+
+ return ret;
}
EXPORT_SYMBOL(f_setown);
@@ -307,6 +321,8 @@ static long fcntl_rw_hint(struct file *file, unsigned int cmd,
static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
struct file *filp)
{
+ void __user *argp = (void __user *)arg;
+ struct flock flock;
long err = -EINVAL;
switch (cmd) {
@@ -334,7 +350,11 @@ static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
case F_OFD_GETLK:
#endif
case F_GETLK:
- err = fcntl_getlk(filp, cmd, (struct flock __user *) arg);
+ if (copy_from_user(&flock, argp, sizeof(flock)))
+ return -EFAULT;
+ err = fcntl_getlk(filp, cmd, &flock);
+ if (!err && copy_to_user(argp, &flock, sizeof(flock)))
+ return -EFAULT;
break;
#if BITS_PER_LONG != 32
/* 32-bit arches must use fcntl64() */
@@ -344,7 +364,9 @@ static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
/* Fallthrough */
case F_SETLK:
case F_SETLKW:
- err = fcntl_setlk(fd, filp, cmd, (struct flock __user *) arg);
+ if (copy_from_user(&flock, argp, sizeof(flock)))
+ return -EFAULT;
+ err = fcntl_setlk(fd, filp, cmd, &flock);
break;
case F_GETOWN:
/*
@@ -358,8 +380,7 @@ static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
force_successful_syscall_return();
break;
case F_SETOWN:
- f_setown(filp, arg, 1);
- err = 0;
+ err = f_setown(filp, arg, 1);
break;
case F_GETOWN_EX:
err = f_getown_ex(filp, arg);
@@ -450,7 +471,9 @@ out:
SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
unsigned long, arg)
{
+ void __user *argp = (void __user *)arg;
struct fd f = fdget_raw(fd);
+ struct flock64 flock;
long err = -EBADF;
if (!f.file)
@@ -468,14 +491,21 @@ SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
switch (cmd) {
case F_GETLK64:
case F_OFD_GETLK:
- err = fcntl_getlk64(f.file, cmd, (struct flock64 __user *) arg);
+ err = -EFAULT;
+ if (copy_from_user(&flock, argp, sizeof(flock)))
+ break;
+ err = fcntl_getlk64(f.file, cmd, &flock);
+ if (!err && copy_to_user(argp, &flock, sizeof(flock)))
+ err = -EFAULT;
break;
case F_SETLK64:
case F_SETLKW64:
case F_OFD_SETLK:
case F_OFD_SETLKW:
- err = fcntl_setlk64(fd, f.file, cmd,
- (struct flock64 __user *) arg);
+ err = -EFAULT;
+ if (copy_from_user(&flock, argp, sizeof(flock)))
+ break;
+ err = fcntl_setlk64(fd, f.file, cmd, &flock);
break;
default:
err = do_fcntl(fd, cmd, arg, f.file);
@@ -489,57 +519,56 @@ out:
#endif
#ifdef CONFIG_COMPAT
+/* careful - don't use anywhere else */
+#define copy_flock_fields(from, to) \
+ (to).l_type = (from).l_type; \
+ (to).l_whence = (from).l_whence; \
+ (to).l_start = (from).l_start; \
+ (to).l_len = (from).l_len; \
+ (to).l_pid = (from).l_pid;
+
static int get_compat_flock(struct flock *kfl, struct compat_flock __user *ufl)
{
- if (!access_ok(VERIFY_READ, ufl, sizeof(*ufl)) ||
- __get_user(kfl->l_type, &ufl->l_type) ||
- __get_user(kfl->l_whence, &ufl->l_whence) ||
- __get_user(kfl->l_start, &ufl->l_start) ||
- __get_user(kfl->l_len, &ufl->l_len) ||
- __get_user(kfl->l_pid, &ufl->l_pid))
+ struct compat_flock fl;
+
+ if (copy_from_user(&fl, ufl, sizeof(struct compat_flock)))
return -EFAULT;
+ copy_flock_fields(*kfl, fl);
return 0;
}
-static int put_compat_flock(struct flock *kfl, struct compat_flock __user *ufl)
+static int get_compat_flock64(struct flock *kfl, struct compat_flock64 __user *ufl)
{
- if (!access_ok(VERIFY_WRITE, ufl, sizeof(*ufl)) ||
- __put_user(kfl->l_type, &ufl->l_type) ||
- __put_user(kfl->l_whence, &ufl->l_whence) ||
- __put_user(kfl->l_start, &ufl->l_start) ||
- __put_user(kfl->l_len, &ufl->l_len) ||
- __put_user(kfl->l_pid, &ufl->l_pid))
+ struct compat_flock64 fl;
+
+ if (copy_from_user(&fl, ufl, sizeof(struct compat_flock64)))
return -EFAULT;
+ copy_flock_fields(*kfl, fl);
return 0;
}
-#ifndef HAVE_ARCH_GET_COMPAT_FLOCK64
-static int get_compat_flock64(struct flock *kfl, struct compat_flock64 __user *ufl)
+static int put_compat_flock(struct flock *kfl, struct compat_flock __user *ufl)
{
- if (!access_ok(VERIFY_READ, ufl, sizeof(*ufl)) ||
- __get_user(kfl->l_type, &ufl->l_type) ||
- __get_user(kfl->l_whence, &ufl->l_whence) ||
- __get_user(kfl->l_start, &ufl->l_start) ||
- __get_user(kfl->l_len, &ufl->l_len) ||
- __get_user(kfl->l_pid, &ufl->l_pid))
+ struct compat_flock fl;
+
+ memset(&fl, 0, sizeof(struct compat_flock));
+ copy_flock_fields(fl, *kfl);
+ if (copy_to_user(ufl, &fl, sizeof(struct compat_flock)))
return -EFAULT;
return 0;
}
-#endif
-#ifndef HAVE_ARCH_PUT_COMPAT_FLOCK64
static int put_compat_flock64(struct flock *kfl, struct compat_flock64 __user *ufl)
{
- if (!access_ok(VERIFY_WRITE, ufl, sizeof(*ufl)) ||
- __put_user(kfl->l_type, &ufl->l_type) ||
- __put_user(kfl->l_whence, &ufl->l_whence) ||
- __put_user(kfl->l_start, &ufl->l_start) ||
- __put_user(kfl->l_len, &ufl->l_len) ||
- __put_user(kfl->l_pid, &ufl->l_pid))
+ struct compat_flock64 fl;
+
+ memset(&fl, 0, sizeof(struct compat_flock64));
+ copy_flock_fields(fl, *kfl);
+ if (copy_to_user(ufl, &fl, sizeof(struct compat_flock64)))
return -EFAULT;
return 0;
}
-#endif
+#undef copy_flock_fields
static unsigned int
convert_fcntl_cmd(unsigned int cmd)
@@ -556,76 +585,92 @@ convert_fcntl_cmd(unsigned int cmd)
return cmd;
}
+/*
+ * GETLK was successful and we need to return the data, but it needs to fit in
+ * the compat structure.
+ * l_start shouldn't be too big, unless the original start + end is greater than
+ * COMPAT_OFF_T_MAX, in which case the app was asking for trouble, so we return
+ * -EOVERFLOW in that case. l_len could be too big, in which case we just
+ * truncate it, and only allow the app to see that part of the conflicting lock
+ * that might make sense to it anyway
+ */
+static int fixup_compat_flock(struct flock *flock)
+{
+ if (flock->l_start > COMPAT_OFF_T_MAX)
+ return -EOVERFLOW;
+ if (flock->l_len > COMPAT_OFF_T_MAX)
+ flock->l_len = COMPAT_OFF_T_MAX;
+ return 0;
+}
+
COMPAT_SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
compat_ulong_t, arg)
{
- mm_segment_t old_fs;
- struct flock f;
- long ret;
- unsigned int conv_cmd;
+ struct fd f = fdget_raw(fd);
+ struct flock flock;
+ long err = -EBADF;
+
+ if (!f.file)
+ return err;
+
+ if (unlikely(f.file->f_mode & FMODE_PATH)) {
+ if (!check_fcntl_cmd(cmd))
+ goto out_put;
+ }
+
+ err = security_file_fcntl(f.file, cmd, arg);
+ if (err)
+ goto out_put;
switch (cmd) {
case F_GETLK:
+ err = get_compat_flock(&flock, compat_ptr(arg));
+ if (err)
+ break;
+ err = fcntl_getlk(f.file, convert_fcntl_cmd(cmd), &flock);
+ if (err)
+ break;
+ err = fixup_compat_flock(&flock);
+ if (err)
+ return err;
+ err = put_compat_flock(&flock, compat_ptr(arg));
+ break;
+ case F_GETLK64:
+ case F_OFD_GETLK:
+ err = get_compat_flock64(&flock, compat_ptr(arg));
+ if (err)
+ break;
+ err = fcntl_getlk(f.file, convert_fcntl_cmd(cmd), &flock);
+ if (err)
+ break;
+ err = fixup_compat_flock(&flock);
+ if (err)
+ return err;
+ err = put_compat_flock64(&flock, compat_ptr(arg));
+ break;
case F_SETLK:
case F_SETLKW:
- ret = get_compat_flock(&f, compat_ptr(arg));
- if (ret != 0)
+ err = get_compat_flock(&flock, compat_ptr(arg));
+ if (err)
break;
- old_fs = get_fs();
- set_fs(KERNEL_DS);
- ret = sys_fcntl(fd, cmd, (unsigned long)&f);
- set_fs(old_fs);
- if (cmd == F_GETLK && ret == 0) {
- /* GETLK was successful and we need to return the data...
- * but it needs to fit in the compat structure.
- * l_start shouldn't be too big, unless the original
- * start + end is greater than COMPAT_OFF_T_MAX, in which
- * case the app was asking for trouble, so we return
- * -EOVERFLOW in that case.
- * l_len could be too big, in which case we just truncate it,
- * and only allow the app to see that part of the conflicting
- * lock that might make sense to it anyway
- */
-
- if (f.l_start > COMPAT_OFF_T_MAX)
- ret = -EOVERFLOW;
- if (f.l_len > COMPAT_OFF_T_MAX)
- f.l_len = COMPAT_OFF_T_MAX;
- if (ret == 0)
- ret = put_compat_flock(&f, compat_ptr(arg));
- }
+ err = fcntl_setlk(fd, f.file, convert_fcntl_cmd(cmd), &flock);
break;
-
- case F_GETLK64:
case F_SETLK64:
case F_SETLKW64:
- case F_OFD_GETLK:
case F_OFD_SETLK:
case F_OFD_SETLKW:
- ret = get_compat_flock64(&f, compat_ptr(arg));
- if (ret != 0)
+ err = get_compat_flock64(&flock, compat_ptr(arg));
+ if (err)
break;
- old_fs = get_fs();
- set_fs(KERNEL_DS);
- conv_cmd = convert_fcntl_cmd(cmd);
- ret = sys_fcntl(fd, conv_cmd, (unsigned long)&f);
- set_fs(old_fs);
- if ((conv_cmd == F_GETLK || conv_cmd == F_OFD_GETLK) && ret == 0) {
- /* need to return lock information - see above for commentary */
- if (f.l_start > COMPAT_LOFF_T_MAX)
- ret = -EOVERFLOW;
- if (f.l_len > COMPAT_LOFF_T_MAX)
- f.l_len = COMPAT_LOFF_T_MAX;
- if (ret == 0)
- ret = put_compat_flock64(&f, compat_ptr(arg));
- }
+ err = fcntl_setlk(fd, f.file, convert_fcntl_cmd(cmd), &flock);
break;
-
default:
- ret = sys_fcntl(fd, cmd, arg);
+ err = do_fcntl(fd, cmd, arg, f.file);
break;
}
- return ret;
+out_put:
+ fdput(f);
+ return err;
}
COMPAT_SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd,