fcntl: don't cap l_start and l_end values for F_GETLK64 in compat syscall

commit 4d2dc2cc766c3b51929658cacbc6e34fc8e242fb upstream.

Currently, we're capping the values too low in the F_GETLK64 case. The
fields in that structure are 64-bit values, so we shouldn't need to do
any sort of fixup there.

Make sure we check that assumption at build time in the future however
by ensuring that the sizes we're copying will fit.

With this, we no longer need COMPAT_LOFF_T_MAX either, so remove it.

Fixes: 94073ad77fff2 (fs/locks: don't mess with the address limit in compat_fcntl64)
Reported-by: Vitaly Lipatov <lav@etersoft.ru>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

9 files changed, 5 insertions, 14 deletions

diff --git a/arch/arm64/include/asm/compat.h b/arch/arm64/include/asm/compat.h
index e39d487bf724..a3c7f271ad4c 100644
--- a/arch/arm64/include/asm/compat.h
+++ b/arch/arm64/include/asm/compat.h
@@ -215,7 +215,6 @@ typedef struct compat_siginfo {
 } compat_siginfo_t;
 
 #define COMPAT_OFF_T_MAX	0x7fffffff
-#define COMPAT_LOFF_T_MAX	0x7fffffffffffffffL
 
 /*
  * A pointer passed in from user mode. This should not
diff --git a/arch/mips/include/asm/compat.h b/arch/mips/include/asm/compat.h
index 8e2b5b556488..49691331ada4 100644
--- a/arch/mips/include/asm/compat.h
+++ b/arch/mips/include/asm/compat.h
@@ -200,7 +200,6 @@ typedef struct compat_siginfo {
 } compat_siginfo_t;
 
 #define COMPAT_OFF_T_MAX	0x7fffffff
-#define COMPAT_LOFF_T_MAX	0x7fffffffffffffffL
 
 /*
  * A pointer passed in from user mode. This should not
diff --git a/arch/parisc/include/asm/compat.h b/arch/parisc/include/asm/compat.h
index 07f48827afda..acf8aa07cbe0 100644
--- a/arch/parisc/include/asm/compat.h
+++ b/arch/parisc/include/asm/compat.h
@@ -195,7 +195,6 @@ typedef struct compat_siginfo {
 } compat_siginfo_t;
 
 #define COMPAT_OFF_T_MAX	0x7fffffff
-#define COMPAT_LOFF_T_MAX	0x7fffffffffffffffL
 
 struct compat_ipc64_perm {
 	compat_key_t key;
diff --git a/arch/powerpc/include/asm/compat.h b/arch/powerpc/include/asm/compat.h
index a035b1e5dfa7..8a2aecfe9b02 100644
--- a/arch/powerpc/include/asm/compat.h
+++ b/arch/powerpc/include/asm/compat.h
@@ -185,7 +185,6 @@ typedef struct compat_siginfo {
 } compat_siginfo_t;
 
 #define COMPAT_OFF_T_MAX	0x7fffffff
-#define COMPAT_LOFF_T_MAX	0x7fffffffffffffffL
 
 /*
  * A pointer passed in from user mode. This should not
diff --git a/arch/s390/include/asm/compat.h b/arch/s390/include/asm/compat.h
index 1b60eb3676d5..5e6a63641a5f 100644
--- a/arch/s390/include/asm/compat.h
+++ b/arch/s390/include/asm/compat.h
@@ -263,7 +263,6 @@ typedef struct compat_siginfo {
 #define si_overrun	_sifields._timer._overrun
 
 #define COMPAT_OFF_T_MAX	0x7fffffff
-#define COMPAT_LOFF_T_MAX	0x7fffffffffffffffL
 
 /*
  * A pointer passed in from user mode. This should not
diff --git a/arch/sparc/include/asm/compat.h b/arch/sparc/include/asm/compat.h
index 977c3f280ba1..fa38c78de0f0 100644
--- a/arch/sparc/include/asm/compat.h
+++ b/arch/sparc/include/asm/compat.h
@@ -209,7 +209,6 @@ typedef struct compat_siginfo {
 } compat_siginfo_t;
 
 #define COMPAT_OFF_T_MAX	0x7fffffff
-#define COMPAT_LOFF_T_MAX	0x7fffffffffffffffL
 
 /*
  * A pointer passed in from user mode. This should not
diff --git a/arch/tile/include/asm/compat.h b/arch/tile/include/asm/compat.h
index c14e36f008c8..62a7b83025dd 100644
--- a/arch/tile/include/asm/compat.h
+++ b/arch/tile/include/asm/compat.h
@@ -173,7 +173,6 @@ typedef struct compat_siginfo {
 } compat_siginfo_t;
 
 #define COMPAT_OFF_T_MAX	0x7fffffff
-#define COMPAT_LOFF_T_MAX	0x7fffffffffffffffL
 
 struct compat_ipc64_perm {
 	compat_key_t key;
diff --git a/arch/x86/include/asm/compat.h b/arch/x86/include/asm/compat.h
index 9eef9cc64c68..70bc1df580b2 100644
--- a/arch/x86/include/asm/compat.h
+++ b/arch/x86/include/asm/compat.h
@@ -209,7 +209,6 @@ typedef struct compat_siginfo {
 } compat_siginfo_t;
 
 #define COMPAT_OFF_T_MAX	0x7fffffff
-#define COMPAT_LOFF_T_MAX	0x7fffffffffffffffL
 
 struct compat_ipc64_perm {
 	compat_key_t key;
diff --git a/fs/fcntl.c b/fs/fcntl.c
index 6fd311367efc..0345a46b8856 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -563,6 +563,9 @@ static int put_compat_flock64(const struct flock *kfl, struct compat_flock64 __u
 {
 	struct compat_flock64 fl;
 
+	BUILD_BUG_ON(sizeof(kfl->l_start) > sizeof(ufl->l_start));
+	BUILD_BUG_ON(sizeof(kfl->l_len) > sizeof(ufl->l_len));
+
 	memset(&fl, 0, sizeof(struct compat_flock64));
 	copy_flock_fields(&fl, kfl);
 	if (copy_to_user(ufl, &fl, sizeof(struct compat_flock64)))
@@ -641,12 +644,8 @@ COMPAT_SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
 		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));
+		if (!err)
+			err = put_compat_flock64(&flock, compat_ptr(arg));
 		break;
 	case F_SETLK:
 	case F_SETLKW: