From: Anton Protopopov Subject: [PATCH] ext4: ioctl: fix erroneous return value Date: Thu, 11 Feb 2016 10:58:58 -0500 Message-ID: <1455206338-2869-1-git-send-email-a.s.protopopov@gmail.com> Cc: Anton Protopopov To: "Theodore Ts'o" , Andreas Dilger , linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org Return-path: Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org The ext4_ioctl_setflags() function which is used in the ioctls EXT4_IOC_SETFLAGS and EXT4_IOC_FSSETXATTR may return the positive value EPERM instead of -EPERM in case of error. This bug was introduced by a recent commit 9b7365fc. The following program can be used to illustrate the wrong behavior: #include #include #include #include #include #define FS_IOC_GETFLAGS _IOR('f', 1, long) #define FS_IOC_SETFLAGS _IOW('f', 2, long) #define FS_IMMUTABLE_FL 0x00000010 int main(void) { int fd; long flags; fd = open("file", O_RDWR|O_CREAT, 0600); if (fd < 0) err(1, "open"); if (ioctl(fd, FS_IOC_GETFLAGS, &flags) < 0) err(1, "ioctl: FS_IOC_GETFLAGS"); flags |= FS_IMMUTABLE_FL; if (ioctl(fd, FS_IOC_SETFLAGS, &flags) < 0) err(1, "ioctl: FS_IOC_SETFLAGS"); warnx("ioctl returned no error"); return 0; } Running it gives the following result: $ strace -e ioctl ./test ioctl(3, FS_IOC_GETFLAGS, 0x7ffdbd8bfd38) = 0 ioctl(3, FS_IOC_SETFLAGS, 0x7ffdbd8bfd38) = 1 test: ioctl returned no error +++ exited with 0 +++ Running the program on a kernel with the bug fixed gives the proper result: $ strace -e ioctl ./test ioctl(3, FS_IOC_GETFLAGS, 0x7ffdd2768258) = 0 ioctl(3, FS_IOC_SETFLAGS, 0x7ffdd2768258) = -1 EPERM (Operation not permitted) test: ioctl: FS_IOC_SETFLAGS: Operation not permitted +++ exited with 1 +++ Signed-off-by: Anton Protopopov --- fs/ext4/ioctl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c index 0f6c369..a99b010 100644 --- a/fs/ext4/ioctl.c +++ b/fs/ext4/ioctl.c @@ -208,7 +208,7 @@ static int ext4_ioctl_setflags(struct inode *inode, { struct ext4_inode_info *ei = EXT4_I(inode); handle_t *handle = NULL; - int err = EPERM, migrate = 0; + int err = -EPERM, migrate = 0; struct ext4_iloc iloc; unsigned int oldflags, mask, i; unsigned int jflag; -- 2.6.5