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author | Linus Torvalds <torvalds@linux-foundation.org> | 2020-12-15 19:29:43 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-12-15 19:29:43 -0800 |
commit | faf145d6f3f3d6f2c066f65602ba9d0a03106915 (patch) | |
tree | 17685a9855b048998f734f9114c9cbf94aa61569 /fs/exec.c | |
parent | 6febd8bef36e64fc1f4aaff1f6302be5c653ad64 (diff) | |
parent | 9ee1206dcfb9d56503c0de9f8320f7b29c795867 (diff) | |
download | linux-faf145d6f3f3d6f2c066f65602ba9d0a03106915.tar.bz2 |
Merge branch 'exec-for-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull execve updates from Eric Biederman:
"This set of changes ultimately fixes the interaction of posix file
lock and exec. Fundamentally most of the change is just moving where
unshare_files is called during exec, and tweaking the users of
files_struct so that the count of files_struct is not unnecessarily
played with.
Along the way fcheck and related helpers were renamed to more
accurately reflect what they do.
There were also many other small changes that fell out, as this is the
first time in a long time much of this code has been touched.
Benchmarks haven't turned up any practical issues but Al Viro has
observed a possibility for a lot of pounding on task_lock. So I have
some changes in progress to convert put_files_struct to always rcu
free files_struct. That wasn't ready for the merge window so that will
have to wait until next time"
* 'exec-for-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (27 commits)
exec: Move io_uring_task_cancel after the point of no return
coredump: Document coredump code exclusively used by cell spufs
file: Remove get_files_struct
file: Rename __close_fd_get_file close_fd_get_file
file: Replace ksys_close with close_fd
file: Rename __close_fd to close_fd and remove the files parameter
file: Merge __alloc_fd into alloc_fd
file: In f_dupfd read RLIMIT_NOFILE once.
file: Merge __fd_install into fd_install
proc/fd: In fdinfo seq_show don't use get_files_struct
bpf/task_iter: In task_file_seq_get_next use task_lookup_next_fd_rcu
proc/fd: In proc_readfd_common use task_lookup_next_fd_rcu
file: Implement task_lookup_next_fd_rcu
kcmp: In get_file_raw_ptr use task_lookup_fd_rcu
proc/fd: In tid_fd_mode use task_lookup_fd_rcu
file: Implement task_lookup_fd_rcu
file: Rename fcheck lookup_fd_rcu
file: Replace fcheck_files with files_lookup_fd_rcu
file: Factor files_lookup_fd_locked out of fcheck_files
file: Rename __fcheck_files to files_lookup_fd_raw
...
Diffstat (limited to 'fs/exec.c')
-rw-r--r-- | fs/exec.c | 39 |
1 files changed, 18 insertions, 21 deletions
diff --git a/fs/exec.c b/fs/exec.c index aee36e5733ce..81b85f70e9f3 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1259,6 +1259,16 @@ int begin_new_exec(struct linux_binprm * bprm) goto out; /* + * Cancel any io_uring activity across execve + */ + io_uring_task_cancel(); + + /* Ensure the files table is not shared. */ + retval = unshare_files(); + if (retval) + goto out; + + /* * Must be called _before_ exec_mmap() as bprm->mm is * not visibile until then. This also enables the update * to be lockless. @@ -1779,21 +1789,11 @@ static int bprm_execve(struct linux_binprm *bprm, int fd, struct filename *filename, int flags) { struct file *file; - struct files_struct *displaced; int retval; - /* - * Cancel any io_uring activity across execve - */ - io_uring_task_cancel(); - - retval = unshare_files(&displaced); - if (retval) - return retval; - retval = prepare_bprm_creds(bprm); if (retval) - goto out_files; + return retval; check_unsafe_exec(bprm); current->in_execve = 1; @@ -1808,11 +1808,14 @@ static int bprm_execve(struct linux_binprm *bprm, bprm->file = file; /* * Record that a name derived from an O_CLOEXEC fd will be - * inaccessible after exec. Relies on having exclusive access to - * current->files (due to unshare_files above). + * inaccessible after exec. This allows the code in exec to + * choose to fail when the executable is not mmaped into the + * interpreter and an open file descriptor is not passed to + * the interpreter. This makes for a better user experience + * than having the interpreter start and then immediately fail + * when it finds the executable is inaccessible. */ - if (bprm->fdpath && - close_on_exec(fd, rcu_dereference_raw(current->files->fdt))) + if (bprm->fdpath && get_close_on_exec(fd)) bprm->interp_flags |= BINPRM_FLAGS_PATH_INACCESSIBLE; /* Set the unchanging part of bprm->cred */ @@ -1830,8 +1833,6 @@ static int bprm_execve(struct linux_binprm *bprm, rseq_execve(current); acct_update_integrals(current); task_numa_free(current, false); - if (displaced) - put_files_struct(displaced); return retval; out: @@ -1848,10 +1849,6 @@ out_unmark: current->fs->in_exec = 0; current->in_execve = 0; -out_files: - if (displaced) - reset_files_struct(displaced); - return retval; } |