On Thu 06-05-10 14:30:02, Andrew Morton wrote: > > (switched to email. Please respond via emailed reply-to-all, not via the > bugzilla web interface). > > On Wed, 5 May 2010 13:01:22 GMT > bugzilla-daemon@xxxxxxxxxxxxxxxxxxx wrote: > > > https://bugzilla.kernel.org/show_bug.cgi?id=15909 > > > > Summary: open("a/",O_NOFOLLOW) fails with ELOOP if "a" is a > > symbolic link to a directory. > > Product: File System > > Version: 2.5 > > Kernel Version: 2.6.34-rc6 > > Platform: All > > OS/Version: Linux > > Tree: Mainline > > Status: NEW > > Severity: high > > Priority: P1 > > Component: Other > > AssignedTo: fs_other@xxxxxxxxxxxxxxxxxxxx > > ReportedBy: tolzmann@xxxxxxxxxxxxx > > Regression: No > > > > > > mkdir c > > ln -s c a > > > > f=open("a/",O_RDONLY+O_NOFOLLOW) > > > > fails with ELOOP. However, this open should behave like open("a/.") not like > > open("a") according to path_resolution(7). In kernel version 2.6.32 the open > > worked as documented. > > > > On a higher level this bug makes > > > > find a/ > > > > to fail. > > > > It sounds like this 2.6.32->2.6.34-rc6 regression could have pretty > serious ramifications for some users. Does anyone know whcih commit > might have caused it? The patch below fixes the issue for me but someone should have a look at it because I'm not really an expert in that code and the code paths are so twisted that my mind is currently tied into a knot ;). Honza --- >From d53d3cc6488d9135bb69c3ff7e034b3b624866ed Mon Sep 17 00:00:00 2001 From: Jan Kara <jack@xxxxxxx> Date: Tue, 11 May 2010 16:34:25 +0200 Subject: [PATCH] vfs: Fix O_NOFOLLOW behavior for paths with trailing slashes According to specification mkdir d; ln -s d a; open("a/", O_NOFOLLOW | O_RDONLY) should return success but currently it did return ELOOP. Fix the code to ignore O_NOFOLLOW in case the provided path has trailing slashes. This is a regression caused by path lookup cleanup patch series. CC: stable@xxxxxxxxxx Signed-off-by: Jan Kara <jack@xxxxxxx> --- fs/namei.c | 8 +++++--- 1 files changed, 5 insertions(+), 3 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index a7dce91..4cc7fbc 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1641,7 +1641,7 @@ static struct file *do_last(struct nameidata *nd, struct path *path, if (nd->last.name[nd->last.len]) { if (open_flag & O_CREAT) goto exit; - nd->flags |= LOOKUP_DIRECTORY; + nd->flags |= LOOKUP_DIRECTORY | LOOKUP_FOLLOW; } /* just plain open? */ @@ -1722,7 +1722,7 @@ static struct file *do_last(struct nameidata *nd, struct path *path, if (__follow_mount(path)) { error = -ELOOP; - if (open_flag & O_NOFOLLOW) + if (!(nd->flags & LOOKUP_FOLLOW)) goto exit_dput; } @@ -1830,6 +1830,8 @@ reval: } if (open_flag & O_DIRECTORY) nd.flags |= LOOKUP_DIRECTORY; + if (!(open_flag & O_NOFOLLOW)) + nd.flags |= LOOKUP_FOLLOW; filp = do_last(&nd, &path, open_flag, acc_mode, mode, pathname); while (unlikely(!filp)) { /* trailing symlink */ struct path holder; @@ -1837,7 +1839,7 @@ reval: void *cookie; error = -ELOOP; /* S_ISDIR part is a temporary automount kludge */ - if ((open_flag & O_NOFOLLOW) && !S_ISDIR(inode->i_mode)) + if (!(nd.flags & LOOKUP_FOLLOW) && !S_ISDIR(inode->i_mode)) goto exit_dput; if (count++ == 32) goto exit_dput; -- 1.6.4.2 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
