Since seq_read_iter looks mature enough to be used for all procfs files, re-allow applications to perform zero-copy data forwarding from them. According to the sendfile(2) man-page, it is still enough for the file being read to support mmap-like operations, and the proc files support memory mapping, so returning -EINVAL was an inconsistency. Some executable-inspecting tools rely on patching entry point instructions with minimal machine code that uses sendfile to read /proc/self/maps to stdout. The sendfile call allows them to do it faster and without excessive allocations. This is inspired by the series by Cristoph Hellwig (linked). Link: https://lore.kernel.org/lkml/20201104082738.1054792-1-hch@xxxxxx/ Fixes: 36e2c7421f02 ("fs: don't allow splice read/write without explicit ops") Cc: Alexey Dobriyan <adobriyan@xxxxxxxxx> Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxx> Signed-off-by: Arkadiusz Kozdra (Arusekk) <arek_koz@xxxxx> --- fs/proc/array.c | 9 +++++---- fs/proc/base.c | 36 ++++++++++++++++++++++++------------ fs/proc/fd.c | 3 ++- fs/proc/proc_net.c | 4 ++-- fs/proc/task_mmu.c | 12 ++++++++---- fs/proc/task_nommu.c | 3 ++- 6 files changed, 43 insertions(+), 24 deletions(-) diff --git a/fs/proc/array.c b/fs/proc/array.c index bb87e4d89cd8..3c3da655a6d0 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -797,9 +797,10 @@ static int children_seq_open(struct inode *inode, struct file *file) } const struct file_operations proc_tid_children_operations = { - .open = children_seq_open, - .read = seq_read, - .llseek = seq_lseek, - .release = seq_release, + .open = children_seq_open, + .read_iter = seq_read_iter, + .splice_read = generic_file_splice_read, + .llseek = seq_lseek, + .release = seq_release, }; #endif /* CONFIG_PROC_CHILDREN */ diff --git a/fs/proc/base.c b/fs/proc/base.c index 3851bfcdba56..b9921a0c2d3d 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -535,7 +535,8 @@ static ssize_t lstats_write(struct file *file, const char __user *buf, static const struct file_operations proc_lstats_operations = { .open = lstats_open, - .read = seq_read, + .read_iter = seq_read_iter, + .splice_read = generic_file_splice_read, .write = lstats_write, .llseek = seq_lseek, .release = single_release, @@ -784,7 +785,8 @@ static int proc_single_open(struct inode *inode, struct file *filp) static const struct file_operations proc_single_file_operations = { .open = proc_single_open, - .read = seq_read, + .read_iter = seq_read_iter, + .splice_read = generic_file_splice_read, .llseek = seq_lseek, .release = single_release, }; @@ -1473,7 +1475,8 @@ static int sched_open(struct inode *inode, struct file *filp) static const struct file_operations proc_pid_sched_operations = { .open = sched_open, - .read = seq_read, + .read_iter = seq_read_iter, + .splice_read = generic_file_splice_read, .write = sched_write, .llseek = seq_lseek, .release = single_release, @@ -1548,7 +1551,8 @@ static int sched_autogroup_open(struct inode *inode, struct file *filp) static const struct file_operations proc_pid_sched_autogroup_operations = { .open = sched_autogroup_open, - .read = seq_read, + .read_iter = seq_read_iter, + .splice_read = generic_file_splice_read, .write = sched_autogroup_write, .llseek = seq_lseek, .release = single_release, @@ -1651,7 +1655,8 @@ static int timens_offsets_open(struct inode *inode, struct file *filp) static const struct file_operations proc_timens_offsets_operations = { .open = timens_offsets_open, - .read = seq_read, + .read_iter = seq_read_iter, + .splice_read = generic_file_splice_read, .write = timens_offsets_write, .llseek = seq_lseek, .release = single_release, @@ -1708,7 +1713,8 @@ static int comm_open(struct inode *inode, struct file *filp) static const struct file_operations proc_pid_set_comm_operations = { .open = comm_open, - .read = seq_read, + .read_iter = seq_read_iter, + .splice_read = generic_file_splice_read, .write = comm_write, .llseek = seq_lseek, .release = single_release, @@ -2497,7 +2503,8 @@ static int proc_timers_open(struct inode *inode, struct file *file) static const struct file_operations proc_timers_operations = { .open = proc_timers_open, - .read = seq_read, + .read_iter = seq_read_iter, + .splice_read = generic_file_splice_read, .llseek = seq_lseek, .release = seq_release_private, }; @@ -2589,7 +2596,8 @@ static int timerslack_ns_open(struct inode *inode, struct file *filp) static const struct file_operations proc_pid_set_timerslack_ns_operations = { .open = timerslack_ns_open, - .read = seq_read, + .read_iter = seq_read_iter, + .splice_read = generic_file_splice_read, .write = timerslack_ns_write, .llseek = seq_lseek, .release = single_release, @@ -3041,7 +3049,8 @@ static int proc_projid_map_open(struct inode *inode, struct file *file) static const struct file_operations proc_uid_map_operations = { .open = proc_uid_map_open, .write = proc_uid_map_write, - .read = seq_read, + .read_iter = seq_read_iter, + .splice_read = generic_file_splice_read, .llseek = seq_lseek, .release = proc_id_map_release, }; @@ -3049,7 +3058,8 @@ static const struct file_operations proc_uid_map_operations = { static const struct file_operations proc_gid_map_operations = { .open = proc_gid_map_open, .write = proc_gid_map_write, - .read = seq_read, + .read_iter = seq_read_iter, + .splice_read = generic_file_splice_read, .llseek = seq_lseek, .release = proc_id_map_release, }; @@ -3057,7 +3067,8 @@ static const struct file_operations proc_gid_map_operations = { static const struct file_operations proc_projid_map_operations = { .open = proc_projid_map_open, .write = proc_projid_map_write, - .read = seq_read, + .read_iter = seq_read_iter, + .splice_read = generic_file_splice_read, .llseek = seq_lseek, .release = proc_id_map_release, }; @@ -3108,7 +3119,8 @@ static int proc_setgroups_release(struct inode *inode, struct file *file) static const struct file_operations proc_setgroups_operations = { .open = proc_setgroups_open, .write = proc_setgroups_write, - .read = seq_read, + .read_iter = seq_read_iter, + .splice_read = generic_file_splice_read, .llseek = seq_lseek, .release = proc_setgroups_release, }; diff --git a/fs/proc/fd.c b/fs/proc/fd.c index 07fc4fad2602..9fa169f05548 100644 --- a/fs/proc/fd.c +++ b/fs/proc/fd.c @@ -77,7 +77,8 @@ static int seq_fdinfo_open(struct inode *inode, struct file *file) static const struct file_operations proc_fdinfo_file_operations = { .open = seq_fdinfo_open, - .read = seq_read, + .read_iter = seq_read_iter, + .splice_read = generic_file_splice_read, .llseek = seq_lseek, .release = single_release, }; diff --git a/fs/proc/proc_net.c b/fs/proc/proc_net.c index 15c2e55d2ed2..a223480189f9 100644 --- a/fs/proc/proc_net.c +++ b/fs/proc/proc_net.c @@ -76,7 +76,7 @@ static int seq_release_net(struct inode *ino, struct file *f) static const struct proc_ops proc_net_seq_ops = { .proc_open = seq_open_net, - .proc_read = seq_read, + .proc_read_iter = seq_read_iter, .proc_write = proc_simple_write, .proc_lseek = seq_lseek, .proc_release = seq_release_net, @@ -188,7 +188,7 @@ static int single_release_net(struct inode *ino, struct file *f) static const struct proc_ops proc_net_single_ops = { .proc_open = single_open_net, - .proc_read = seq_read, + .proc_read_iter = seq_read_iter, .proc_write = proc_simple_write, .proc_lseek = seq_lseek, .proc_release = single_release_net, diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index e862cab69583..7655f5018945 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -351,7 +351,8 @@ static int pid_maps_open(struct inode *inode, struct file *file) const struct file_operations proc_pid_maps_operations = { .open = pid_maps_open, - .read = seq_read, + .read_iter = seq_read_iter, + .splice_read = generic_file_splice_read, .llseek = seq_lseek, .release = proc_map_release, }; @@ -1009,14 +1010,16 @@ static int smaps_rollup_release(struct inode *inode, struct file *file) const struct file_operations proc_pid_smaps_operations = { .open = pid_smaps_open, - .read = seq_read, + .read_iter = seq_read_iter, + .splice_read = generic_file_splice_read, .llseek = seq_lseek, .release = proc_map_release, }; const struct file_operations proc_pid_smaps_rollup_operations = { .open = smaps_rollup_open, - .read = seq_read, + .read_iter = seq_read_iter, + .splice_read = generic_file_splice_read, .llseek = seq_lseek, .release = smaps_rollup_release, }; @@ -1947,7 +1950,8 @@ static int pid_numa_maps_open(struct inode *inode, struct file *file) const struct file_operations proc_pid_numa_maps_operations = { .open = pid_numa_maps_open, - .read = seq_read, + .read_iter = seq_read_iter, + .splice_read = generic_file_splice_read, .llseek = seq_lseek, .release = proc_map_release, }; diff --git a/fs/proc/task_nommu.c b/fs/proc/task_nommu.c index a6d21fc0033c..d17f929ad8a7 100644 --- a/fs/proc/task_nommu.c +++ b/fs/proc/task_nommu.c @@ -295,7 +295,8 @@ static int pid_maps_open(struct inode *inode, struct file *file) const struct file_operations proc_pid_maps_operations = { .open = pid_maps_open, - .read = seq_read, + .read_iter = seq_read_iter, + .splice_read = generic_file_splice_read, .llseek = seq_lseek, .release = map_release, }; -- 2.31.1
