From 4d4621c76afca5d6de642439fa2a5a60b9f1d2c5 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Thu, 15 Apr 2021 17:36:20 +0800 Subject: [PATCH] io_uring: add ->show_fdinfo() for the io_uring file descriptor mainline inclusion from mainline-5.6-rc1 commit 87ce955b24c9940cb2ca7e5173fcf175578d9fe9 category: feature bugzilla: https://bugzilla.openeuler.org/show_bug.cgi?id=27 CVE: NA --------------------------- It can be hard to know exactly what is registered with the ring. Especially for credentials, it'd be handy to be able to see which ones are registered, what personalities they have, and what the ID of each of them is. This adds support for showing information registered in the ring from the fdinfo of the io_uring fd. Here's an example from a test case that registers 4 files (two of them sparse), 4 buffers, and 2 personalities: pos: 0 flags: 02000002 mnt_id: 14 UserFiles: 4 0: file-no-1 1: file-no-2 2: 3: UserBufs: 4 0: 0x563817c46000/128 1: 0x563817c47000/256 2: 0x563817c48000/512 3: 0x563817c49000/1024 Personalities: 1 Uid: 0 0 0 0 Gid: 0 0 0 0 Groups: 0 CapEff: 0000003fffffffff 2 Uid: 0 0 0 0 Gid: 0 0 0 0 Groups: 0 CapEff: 0000003fffffffff Suggested-by: Jann Horn Signed-off-by: Jens Axboe Signed-off-by: yangerkun Reviewed-by: zhangyi (F) Signed-off-by: Cheng Jian --- fs/io_uring.c | 75 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 75 insertions(+) diff --git a/fs/io_uring.c b/fs/io_uring.c index d4e5f2ec8151..b60e528741d5 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -6443,6 +6443,80 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit, return submitted ? submitted : ret; } +static int io_uring_show_cred(int id, void *p, void *data) +{ + const struct cred *cred = p; + struct seq_file *m = data; + struct user_namespace *uns = seq_user_ns(m); + struct group_info *gi; + kernel_cap_t cap; + unsigned __capi; + int g; + + seq_printf(m, "%5d\n", id); + seq_put_decimal_ull(m, "\tUid:\t", from_kuid_munged(uns, cred->uid)); + seq_put_decimal_ull(m, "\t\t", from_kuid_munged(uns, cred->euid)); + seq_put_decimal_ull(m, "\t\t", from_kuid_munged(uns, cred->suid)); + seq_put_decimal_ull(m, "\t\t", from_kuid_munged(uns, cred->fsuid)); + seq_put_decimal_ull(m, "\n\tGid:\t", from_kgid_munged(uns, cred->gid)); + seq_put_decimal_ull(m, "\t\t", from_kgid_munged(uns, cred->egid)); + seq_put_decimal_ull(m, "\t\t", from_kgid_munged(uns, cred->sgid)); + seq_put_decimal_ull(m, "\t\t", from_kgid_munged(uns, cred->fsgid)); + seq_puts(m, "\n\tGroups:\t"); + gi = cred->group_info; + for (g = 0; g < gi->ngroups; g++) { + seq_put_decimal_ull(m, g ? " " : "", + from_kgid_munged(uns, gi->gid[g])); + } + seq_puts(m, "\n\tCapEff:\t"); + cap = cred->cap_effective; + CAP_FOR_EACH_U32(__capi) + seq_put_hex_ll(m, NULL, cap.cap[CAP_LAST_U32 - __capi], 8); + seq_putc(m, '\n'); + return 0; +} + +static void __io_uring_show_fdinfo(struct io_ring_ctx *ctx, struct seq_file *m) +{ + int i; + + mutex_lock(&ctx->uring_lock); + seq_printf(m, "UserFiles:\t%u\n", ctx->nr_user_files); + for (i = 0; i < ctx->nr_user_files; i++) { + struct fixed_file_table *table; + struct file *f; + + table = &ctx->file_data->table[i >> IORING_FILE_TABLE_SHIFT]; + f = table->files[i & IORING_FILE_TABLE_MASK]; + if (f) + seq_printf(m, "%5u: %s\n", i, file_dentry(f)->d_iname); + else + seq_printf(m, "%5u: \n", i); + } + seq_printf(m, "UserBufs:\t%u\n", ctx->nr_user_bufs); + for (i = 0; i < ctx->nr_user_bufs; i++) { + struct io_mapped_ubuf *buf = &ctx->user_bufs[i]; + + seq_printf(m, "%5u: 0x%llx/%u\n", i, buf->ubuf, + (unsigned int) buf->len); + } + if (!idr_is_empty(&ctx->personality_idr)) { + seq_printf(m, "Personalities:\n"); + idr_for_each(&ctx->personality_idr, io_uring_show_cred, m); + } + mutex_unlock(&ctx->uring_lock); +} + +static void io_uring_show_fdinfo(struct seq_file *m, struct file *f) +{ + struct io_ring_ctx *ctx = f->private_data; + + if (percpu_ref_tryget(&ctx->refs)) { + __io_uring_show_fdinfo(ctx, m); + percpu_ref_put(&ctx->refs); + } +} + static const struct file_operations io_uring_fops = { .release = io_uring_release, .flush = io_uring_flush, @@ -6453,6 +6527,7 @@ static const struct file_operations io_uring_fops = { #endif .poll = io_uring_poll, .fasync = io_uring_fasync, + .show_fdinfo = io_uring_show_fdinfo, }; static int io_allocate_scq_urings(struct io_ring_ctx *ctx, -- GitLab