From b74360369e13a68337a411efba1fd2bdbb6f1b80 Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Mon, 8 Jun 2026 02:44:57 -0700 Subject: [PATCH 1/2] selftests: net: rds: add getsockopt() conversion test Add a kselftest that exercises the RDS getsockopt() paths converted to the getsockopt_iter() / sockopt_t callback: - RDS_RECVERR and SO_RDS_TRANSPORT, which return their int value through copy_to_iter() and report the written length in opt->optlen. - RDS_INFO_*, which obtains the userspace buffer pages with iov_iter_extract_pages() (including a non-zero starting page offset) and lets the info producers copy the snapshot in under a spinlock. Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Breno Leitao Reviewed-by: Allison Henderson Link: https://patch.msgid.link/20260608-getsock_more-v3-1-706ecf2ea332@debian.org Signed-off-by: Paolo Abeni --- tools/testing/selftests/net/rds/.gitignore | 1 + tools/testing/selftests/net/rds/Makefile | 4 + tools/testing/selftests/net/rds/getsockopt.c | 208 +++++++++++++++++++ 3 files changed, 213 insertions(+) create mode 100644 tools/testing/selftests/net/rds/getsockopt.c diff --git a/tools/testing/selftests/net/rds/.gitignore b/tools/testing/selftests/net/rds/.gitignore index 1c6f04e2aa11..7ca4b1440f51 100644 --- a/tools/testing/selftests/net/rds/.gitignore +++ b/tools/testing/selftests/net/rds/.gitignore @@ -1 +1,2 @@ include.sh +getsockopt diff --git a/tools/testing/selftests/net/rds/Makefile b/tools/testing/selftests/net/rds/Makefile index ec10ae24e4cf..ab9e92399a6d 100644 --- a/tools/testing/selftests/net/rds/Makefile +++ b/tools/testing/selftests/net/rds/Makefile @@ -5,6 +5,8 @@ all: TEST_PROGS := rds_run.sh +TEST_GEN_PROGS := getsockopt + TEST_FILES := \ include.sh \ settings \ @@ -16,4 +18,6 @@ EXTRA_CLEAN := \ /tmp/rds_logs \ # end of EXTRA_CLEAN +CFLAGS += $(KHDR_INCLUDES) + include ../../lib.mk diff --git a/tools/testing/selftests/net/rds/getsockopt.c b/tools/testing/selftests/net/rds/getsockopt.c new file mode 100644 index 000000000000..93ff252c69b8 --- /dev/null +++ b/tools/testing/selftests/net/rds/getsockopt.c @@ -0,0 +1,208 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Exercise the RDS getsockopt() paths that were converted to the + * getsockopt_iter() / sockopt_t callback. + * + * Three distinct paths are covered: + * + * - RDS_RECVERR and SO_RDS_TRANSPORT, which now return their int value + * through copy_to_iter() and report the written length in opt->optlen. + * + * - RDS_INFO_*, which pins the userspace buffer with + * iov_iter_extract_pages() (including a non-zero starting page offset) + * and lets the info producers memcpy the snapshot in under a spinlock. + * + * The kvec (in-kernel buffer) -> -EOPNOTSUPP path of rds_info_getsockopt() + * is not reachable from a userspace getsockopt() and so is not tested here. + */ +#include +#include +#include +#include +#include +#include +#include + +#include "../../kselftest_harness.h" + +#ifndef AF_RDS +#define AF_RDS 21 +#endif + +FIXTURE(rds) { + int fd; +}; + +FIXTURE_SETUP(rds) +{ + self->fd = socket(AF_RDS, SOCK_SEQPACKET, 0); + if (self->fd < 0) + SKIP(return, "AF_RDS unavailable (errno %d) - load the rds module", + errno); +} + +FIXTURE_TEARDOWN(rds) +{ + if (self->fd >= 0) + close(self->fd); +} + +/* RDS_RECVERR defaults to 0 and is reported back as a 4-byte int. */ +TEST_F(rds, recverr_default) +{ + socklen_t len = sizeof(int); + int val = 0xdeadbeef; + + ASSERT_EQ(0, getsockopt(self->fd, SOL_RDS, RDS_RECVERR, &val, &len)); + EXPECT_EQ(sizeof(int), len); + EXPECT_EQ(0, val); +} + +/* A value set via setsockopt() must be readable back unchanged. */ +TEST_F(rds, recverr_set_get) +{ + socklen_t len = sizeof(int); + int val = 1; + + ASSERT_EQ(0, setsockopt(self->fd, SOL_RDS, RDS_RECVERR, &val, len)); + + val = 0; + ASSERT_EQ(0, getsockopt(self->fd, SOL_RDS, RDS_RECVERR, &val, &len)); + EXPECT_EQ(sizeof(int), len); + EXPECT_EQ(1, val); +} + +/* A buffer smaller than an int is rejected with EINVAL, not silently. */ +TEST_F(rds, recverr_short_buffer) +{ + socklen_t len = sizeof(int) - 1; + char buf[sizeof(int)]; + + EXPECT_EQ(-1, getsockopt(self->fd, SOL_RDS, RDS_RECVERR, buf, &len)); + EXPECT_EQ(EINVAL, errno); +} + +/* An unbound socket reports RDS_TRANS_NONE for SO_RDS_TRANSPORT. */ +TEST_F(rds, transport_unbound) +{ + socklen_t len = sizeof(int); + int val = 0; + + ASSERT_EQ(0, getsockopt(self->fd, SOL_RDS, SO_RDS_TRANSPORT, &val, + &len)); + EXPECT_EQ(sizeof(int), len); + EXPECT_EQ(RDS_TRANS_NONE, (unsigned int)val); +} + +TEST_F(rds, transport_short_buffer) +{ + socklen_t len = sizeof(int) - 1; + char buf[sizeof(int)]; + + EXPECT_EQ(-1, getsockopt(self->fd, SOL_RDS, SO_RDS_TRANSPORT, buf, + &len)); + EXPECT_EQ(EINVAL, errno); +} + +/* + * RDS_INFO_COUNTERS with a zero-length buffer is the "probe" call: it must + * fail with ENOSPC and report the required snapshot size in optlen. + */ +TEST_F(rds, info_counters_probe) +{ + socklen_t len = 0; + + EXPECT_EQ(-1, getsockopt(self->fd, SOL_RDS, RDS_INFO_COUNTERS, NULL, + &len)); + EXPECT_EQ(ENOSPC, errno); + EXPECT_GT(len, 0); + /* The snapshot is an array of fixed-size counter records. */ + EXPECT_EQ(0, len % (socklen_t)sizeof(struct rds_info_counter)); +} + +/* + * A real snapshot into an unaligned userspace buffer exercises the + * iov_iter_extract_pages() path, including the non-zero offset0 handling + * that the patch reworked. Place the buffer at a non-page-aligned address + * spanning into the next page to make sure multi-page pinning works too. + */ +TEST_F(rds, info_counters_snapshot) +{ + struct rds_info_counter *ctr; + socklen_t need = 0, len; + long pagesz = sysconf(_SC_PAGESIZE); + size_t offset, map_len; + unsigned int i, n; + char *region, *buf; + int ret; + + /* Probe for the required size. */ + getsockopt(self->fd, SOL_RDS, RDS_INFO_COUNTERS, NULL, &need); + ASSERT_GT(need, 0); + + /* + * Place the buffer at a non-page-aligned offset that runs past the + * first page boundary, and size the mapping from the probed length so + * the test keeps working if the counter set grows. + */ + offset = pagesz - 64; + map_len = ((offset + need + pagesz - 1) / pagesz) * pagesz; + + region = mmap(NULL, map_len, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + ASSERT_NE(MAP_FAILED, region); + + buf = region + offset; + + /* + * On success the RDS_INFO path returns the positive per-element size + * (lens.each) rather than 0, and writes the full snapshot length back + * into optlen. + */ + len = need; + ret = getsockopt(self->fd, SOL_RDS, RDS_INFO_COUNTERS, buf, &len); + ASSERT_GE(ret, 0) { + TH_LOG("getsockopt snapshot failed: errno %d", errno); + } + EXPECT_EQ(sizeof(struct rds_info_counter), ret); + EXPECT_EQ(need, len); + + /* The counter names must be NUL-terminated, non-empty strings. */ + ctr = (struct rds_info_counter *)buf; + n = len / sizeof(*ctr); + ASSERT_GT(n, 0); + for (i = 0; i < n; i++) { + size_t namelen = strnlen((char *)ctr[i].name, + sizeof(ctr[i].name)); + + EXPECT_GT(namelen, 0); + EXPECT_LT(namelen, sizeof(ctr[i].name)); + } + + munmap(region, map_len); +} + +/* + * A non-zero but too-small buffer must report ENOSPC and the full required + * length, without corrupting memory past the buffer. + */ +TEST_F(rds, info_counters_short_buffer) +{ + socklen_t need = 0, len; + char small[sizeof(struct rds_info_counter)]; + + getsockopt(self->fd, SOL_RDS, RDS_INFO_COUNTERS, NULL, &need); + ASSERT_GT(need, 0); + + /* Ask with a buffer guaranteed smaller than the full snapshot. */ + if (need <= (socklen_t)sizeof(small)) + SKIP(return, "snapshot fits in one record; nothing to test"); + + len = 1; /* < sizeof(struct rds_info_counter) */ + EXPECT_EQ(-1, getsockopt(self->fd, SOL_RDS, RDS_INFO_COUNTERS, small, + &len)); + EXPECT_EQ(ENOSPC, errno); + EXPECT_EQ(need, len); +} + +TEST_HARNESS_MAIN From 6e94eeb2a2a699217fe013844918f542278fc57e Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Mon, 8 Jun 2026 02:44:58 -0700 Subject: [PATCH 2/2] rds: convert to getsockopt_iter Convert RDS socket's getsockopt implementation to use the new getsockopt_iter callback with sockopt_t. Key changes: - Replace (char __user *optval, int __user *optlen) with sockopt_t *opt - Use opt->optlen for buffer length (input) and returned size (output) - Use copy_to_iter() instead of put_user()/copy_to_user() The RDS_INFO_* snapshot path in rds_info_getsockopt() used to pin the userspace buffer with pin_user_pages_fast() on the raw optval address; the info producers then memcpy into those pages under a spinlock via kmap_atomic() and so must not fault. Obtain the same page array and starting offset from opt->iter_out with iov_iter_extract_pages(), which pins for write because iter_out is ITER_DEST. The page array is preallocated here (sized with iov_iter_npages()) and passed in, so iov_iter_extract_pages() fills it in place rather than allocating one for us; RDS therefore keeps ownership of the array on every return path and frees it itself. The rds_info_iterator / rds_info_copy machinery and all producer callbacks are unchanged. Kernel buffers (ITER_KVEC) are not page-backed in a way the info producers can use, so the RDS_INFO path returns -EOPNOTSUPP for them; this matches the previous behaviour, where a kernel-buffer getsockopt hit the WARN_ONCE() path in do_sock_getsockopt() and returned -EOPNOTSUPP. The simple RDS_RECVERR and SO_RDS_TRANSPORT options keep working for kernel buffers via copy_to_iter(). Signed-off-by: Breno Leitao Reviewed-by: Allison Henderson Link: https://patch.msgid.link/20260608-getsock_more-v3-2-706ecf2ea332@debian.org Signed-off-by: Paolo Abeni --- net/rds/af_rds.c | 36 +++++++++++++---------- net/rds/info.c | 76 ++++++++++++++++++++++++++++-------------------- net/rds/info.h | 3 +- 3 files changed, 65 insertions(+), 50 deletions(-) diff --git a/net/rds/af_rds.c b/net/rds/af_rds.c index 6f4f9cf352bd..d5defe9172e3 100644 --- a/net/rds/af_rds.c +++ b/net/rds/af_rds.c @@ -37,6 +37,7 @@ #include #include #include +#include #include #include "rds.h" @@ -485,35 +486,36 @@ static int rds_setsockopt(struct socket *sock, int level, int optname, } static int rds_getsockopt(struct socket *sock, int level, int optname, - char __user *optval, int __user *optlen) + sockopt_t *opt) { struct rds_sock *rs = rds_sk_to_rs(sock->sk); int ret = -ENOPROTOOPT, len; int trans; + int val; if (level != SOL_RDS) goto out; - if (get_user(len, optlen)) { - ret = -EFAULT; - goto out; - } + len = opt->optlen; switch (optname) { case RDS_INFO_FIRST ... RDS_INFO_LAST: - ret = rds_info_getsockopt(sock, optname, optval, - optlen); + ret = rds_info_getsockopt(sock, optname, opt); break; case RDS_RECVERR: - if (len < sizeof(int)) + if (len < sizeof(int)) { ret = -EINVAL; - else - if (put_user(rs->rs_recverr, (int __user *) optval) || - put_user(sizeof(int), optlen)) + break; + } + val = rs->rs_recverr; + if (copy_to_iter(&val, sizeof(int), &opt->iter_out) != + sizeof(int)) { ret = -EFAULT; - else + } else { + opt->optlen = sizeof(int); ret = 0; + } break; case SO_RDS_TRANSPORT: if (len < sizeof(int)) { @@ -522,11 +524,13 @@ static int rds_getsockopt(struct socket *sock, int level, int optname, } trans = (rs->rs_transport ? rs->rs_transport->t_type : RDS_TRANS_NONE); /* unbound */ - if (put_user(trans, (int __user *)optval) || - put_user(sizeof(int), optlen)) + if (copy_to_iter(&trans, sizeof(int), &opt->iter_out) != + sizeof(int)) { ret = -EFAULT; - else + } else { + opt->optlen = sizeof(int); ret = 0; + } break; default: break; @@ -653,7 +657,7 @@ static const struct proto_ops rds_proto_ops = { .listen = sock_no_listen, .shutdown = sock_no_shutdown, .setsockopt = rds_setsockopt, - .getsockopt = rds_getsockopt, + .getsockopt_iter = rds_getsockopt, .sendmsg = rds_sendmsg, .recvmsg = rds_recvmsg, .mmap = sock_no_mmap, diff --git a/net/rds/info.c b/net/rds/info.c index f1b29994934a..499b3774860e 100644 --- a/net/rds/info.c +++ b/net/rds/info.c @@ -35,6 +35,7 @@ #include #include #include +#include #include "rds.h" @@ -144,39 +145,41 @@ void rds_info_copy(struct rds_info_iterator *iter, void *data, EXPORT_SYMBOL_GPL(rds_info_copy); /* - * @optval points to the userspace buffer that the information snapshot - * will be copied into. - * - * @optlen on input is the size of the buffer in userspace. @optlen - * on output is the size of the requested snapshot in bytes. + * @opt->iter_out describes the buffer that the information snapshot will be + * copied into, and @opt->optlen is the size of that buffer on input. On + * output @opt->optlen is set to the size of the requested snapshot in bytes. * * This function returns -errno if there is a failure, particularly -ENOSPC - * if the given userspace buffer was not large enough to fit the snapshot. - * On success it returns the positive number of bytes of each array element - * in the snapshot. + * if the given buffer was not large enough to fit the snapshot. On success + * it returns the positive number of bytes of each array element in the + * snapshot. */ -int rds_info_getsockopt(struct socket *sock, int optname, char __user *optval, - int __user *optlen) +int rds_info_getsockopt(struct socket *sock, int optname, sockopt_t *opt) { struct rds_info_iterator iter; struct rds_info_lengths lens; unsigned long nr_pages = 0; - unsigned long start; rds_info_func func; struct page **pages = NULL; + size_t offset0 = 0; + int npages = 0; int ret; int len; int total; - if (get_user(len, optlen)) { - ret = -EFAULT; + len = opt->optlen; + + /* check for all kinds of wrapping and the like */ + if (len < 0 || len > INT_MAX - PAGE_SIZE + 1) { + ret = -EINVAL; goto out; } - /* check for all kinds of wrapping and the like */ - start = (unsigned long)optval; - if (len < 0 || len > INT_MAX - PAGE_SIZE + 1 || start + len < start) { - ret = -EINVAL; + /* The info producers write into the pages with kmap_atomic() while + * holding a spinlock, so they need a genuine page-backed user buffer. + */ + if (!user_backed_iter(&opt->iter_out)) { + ret = -EOPNOTSUPP; goto out; } @@ -184,20 +187,26 @@ int rds_info_getsockopt(struct socket *sock, int optname, char __user *optval, if (len == 0) goto call_func; - nr_pages = (PAGE_ALIGN(start + len) - (start & PAGE_MASK)) - >> PAGE_SHIFT; - - pages = kmalloc_objs(struct page *, nr_pages); + /* + * Preallocate the page array and pass it in so that + * iov_iter_extract_pages() fills it in place rather than allocating + * one for us. Handing it a non-NULL array keeps ownership of the + * array with us on every return path, instead of depending on the + * iterator code to allocate and hand it back. + */ + npages = iov_iter_npages(&opt->iter_out, INT_MAX); + pages = kvmalloc_array(npages, sizeof(*pages), GFP_KERNEL); if (!pages) { ret = -ENOMEM; goto out; } - ret = pin_user_pages_fast(start, nr_pages, FOLL_WRITE, pages); - if (ret != nr_pages) { - if (ret > 0) - nr_pages = ret; - else - nr_pages = 0; + + ret = iov_iter_extract_pages(&opt->iter_out, &pages, len, npages, + 0, &offset0); + if (ret < 0) + goto out; + nr_pages = DIV_ROUND_UP(offset0 + ret, PAGE_SIZE); + if (ret != len) { ret = -EAGAIN; /* XXX ? */ goto out; } @@ -213,7 +222,7 @@ int rds_info_getsockopt(struct socket *sock, int optname, char __user *optval, iter.pages = pages; iter.addr = NULL; - iter.offset = start & (PAGE_SIZE - 1); + iter.offset = offset0; func(sock, len, &iter, &lens); BUG_ON(lens.each == 0); @@ -230,13 +239,16 @@ int rds_info_getsockopt(struct socket *sock, int optname, char __user *optval, ret = lens.each; } - if (put_user(len, optlen)) - ret = -EFAULT; + opt->optlen = len; out: - if (pages) + /* + * iov_iter_extract_pages() pins only user-backed (ubuf) iters; + * iov_iter_extract_will_pin() reports whether an unpin is owed here. + */ + if (pages && iov_iter_extract_will_pin(&opt->iter_out)) unpin_user_pages(pages, nr_pages); - kfree(pages); + kvfree(pages); return ret; } diff --git a/net/rds/info.h b/net/rds/info.h index a069b51c4679..1aab62ab6d00 100644 --- a/net/rds/info.h +++ b/net/rds/info.h @@ -21,8 +21,7 @@ typedef void (*rds_info_func)(struct socket *sock, unsigned int len, void rds_info_register_func(int optname, rds_info_func func); void rds_info_deregister_func(int optname, rds_info_func func); -int rds_info_getsockopt(struct socket *sock, int optname, char __user *optval, - int __user *optlen); +int rds_info_getsockopt(struct socket *sock, int optname, sockopt_t *opt); void rds_info_copy(struct rds_info_iterator *iter, void *data, unsigned long bytes); void rds_info_iter_unmap(struct rds_info_iterator *iter);