kernel/linux.git/include/linux/sunrpc/svc.h, branch v4.19.68

sunrpc: use-after-free in svc_process_common()

2019-01-16T21:04:37+00:00

commit d4b09acf924b84bae77cad090a9d108e70b43643 upstream. if node have NFSv41+ mounts inside several net namespaces it can lead to use-after-free in svc_process_common() svc_process_common() /* Setup reply header */ rqstp->rq_xprt->xpt_ops->xpo_prep_reply_hdr(rqstp); <<< HERE svc_process_common() can use incorrect rqstp->rq_xprt, its caller function bc_svc_process() takes it from serv->sv_bc_xprt. The problem is that serv is global structure but sv_bc_xprt is assigned per-netnamespace. According to Trond, the whole "let's set up rqstp->rq_xprt for the back channel" is nothing but a giant hack in order to work around the fact that svc_process_common() uses it to find the xpt_ops, and perform a couple of (meaningless for the back channel) tests of xpt_flags. All we really need in svc_process_common() is to be able to run rqstp->rq_xprt->xpt_ops->xpo_prep_reply_hdr() Bruce J Fields points that this xpo_prep_reply_hdr() call is an awfully roundabout way just to do "svc_putnl(resv, 0);" in the tcp case. This patch does not initialiuze rqstp->rq_xprt in bc_svc_process(), now it calls svc_process_common() with rqstp->rq_xprt = NULL. To adjust reply header svc_process_common() just check rqstp->rq_prot and calls svc_tcp_prep_reply_hdr() for tcp case. To handle rqstp->rq_xprt = NULL case in functions called from svc_process_common() patch intruduces net namespace pointer svc_rqst->rq_bc_net and adjust SVC_NET() definition. Some other function was also adopted to properly handle described case. Signed-off-by: Vasily Averin Cc: stable@vger.kernel.org Fixes: 23c20ecd4475 ("NFS: callback up - users counting cleanup") Signed-off-by: J. Bruce Fields v2: added lost extern svc_tcp_prep_reply_hdr() Signed-off-by: Vasily Averin Signed-off-by: Greg Kroah-Hartman

NFSD: Handle full-length symlinks

2018-08-09T20:11:21+00:00

I've given up on the idea of zero-copy handling of SYMLINK on the server side. This is because the Linux VFS symlink API requires the symlink pathname to be in a NUL-terminated kmalloc'd buffer. The NUL-termination is going to be problematic (watching out for landing on a page boundary and dealing with a 4096-byte pathname). I don't believe that SYMLINK creation is on a performance path or is requested frequently enough that it will cause noticeable CPU cache pollution due to data copies. There will be two places where a transport callout will be necessary to fill in the rqstp: one will be in the svc_fill_symlink_pathname() helper that is used by NFSv2 and NFSv3, and the other will be in nfsd4_decode_create(). Signed-off-by: Chuck Lever Signed-off-by: J. Bruce Fields

NFSD: Refactor the generic write vector fill helper

2018-08-09T20:11:21+00:00

fill_in_write_vector() is nearly the same logic as svc_fill_write_vector(), but there are a few differences so that the former can handle multiple WRITE payloads in a single COMPOUND. svc_fill_write_vector() can be adjusted so that it can be used in the NFSv4 WRITE code path too. Instead of assuming the pages are coming from rq_args.pages, have the caller pass in the page list. The immediate benefit is a reduction of code duplication. It also prevents the NFSv4 WRITE decoder from passing an empty vector element when the transport has provided the payload in the xdr_buf's page array. Signed-off-by: Chuck Lever Signed-off-by: J. Bruce Fields

NFSD: Clean up legacy NFS SYMLINK argument XDR decoders

2018-04-03T19:08:16+00:00

Move common code in NFSD's legacy SYMLINK decoders into a helper. The immediate benefits include: - one fewer data copies on transports that support DDP - consistent error checking across all versions - reduction of code duplication - support for both legal forms of SYMLINK requests on RDMA transports for all versions of NFS (in particular, NFSv2, for completeness) In the long term, this helper is an appropriate spot to perform a per-transport call-out to fill the pathname argument using, say, RDMA Reads. Filling the pathname in the proc function also means that eventually the incoming filehandle can be interpreted so that filesystem- specific memory can be allocated as a sink for the pathname argument, rather than using anonymous pages. Signed-off-by: Chuck Lever Signed-off-by: J. Bruce Fields

NFSD: Clean up legacy NFS WRITE argument XDR decoders

2018-04-03T19:08:16+00:00

Move common code in NFSD's legacy NFS WRITE decoders into a helper. The immediate benefit is reduction of code duplication and some nice micro-optimizations (see below). In the long term, this helper can perform a per-transport call-out to fill the rq_vec (say, using RDMA Reads). The legacy WRITE decoders and procs are changed to work like NFSv4, which constructs the rq_vec just before it is about to call vfs_writev. Why? Calling a transport call-out from the proc instead of the XDR decoder means that the incoming FH can be resolved to a particular filesystem and file. This would allow pages from the backing file to be presented to the transport to be filled, rather than presenting anonymous pages and copying or flipping them into the file's page cache later. I also prefer using the pages in rq_arg.pages, instead of pulling the data pages directly out of the rqstp::rq_pages array. This is currently the way the NFSv3 write decoder works, but the other two do not seem to take this approach. Fixing this removes the only reference to rq_pages found in NFSD, eliminating an NFSD assumption about how transports use the pages in rq_pages. Lastly, avoid setting up the first element of rq_vec as a zero- length buffer. This happens with an RDMA transport when a normal Read chunk is present because the data payload is in rq_arg's page list (none of it is in the head buffer). Signed-off-by: Chuck Lever Signed-off-by: J. Bruce Fields

svc: Report xprt dequeue latency

2018-04-03T19:08:13+00:00

Record the time between when a rqstp is enqueued on a transport and when it is dequeued. This includes how long the rqstp waits on the queue and how long it takes the kernel scheduler to wake a nfsd thread to service it. The svc_xprt_dequeue trace point is altered to include the number of microseconds between xprt_enqueue and xprt_dequeue. Signed-off-by: Chuck Lever Signed-off-by: J. Bruce Fields

sunrpc: Report per-RPC execution stats

2018-04-03T19:08:12+00:00

Introduce a mechanism to report the server-side execution latency of each RPC. The goal is to enable user space to filter the trace record for latency outliers, build histograms, etc. Signed-off-by: Chuck Lever Signed-off-by: J. Bruce Fields

Merge tag 'nfsd-4.15' of git://linux-nfs.org/~bfields/linux

2017-11-18T19:22:04+00:00

Pull nfsd updates from Bruce Fields: "Lots of good bugfixes, including: - fix a number of races in the NFSv4+ state code - fix some shutdown crashes in multiple-network-namespace cases - relax our 4.1 session limits; if you've an artificially low limit to the number of 4.1 clients that can mount simultaneously, try upgrading" * tag 'nfsd-4.15' of git://linux-nfs.org/~bfields/linux: (22 commits) SUNRPC: Improve ordering of transport processing nfsd: deal with revoked delegations appropriately svcrdma: Enqueue after setting XPT_CLOSE in completion handlers nfsd: use nfs->ns.inum as net ID rpc: remove some BUG()s svcrdma: Preserve CB send buffer across retransmits nfds: avoid gettimeofday for nfssvc_boot time fs, nfsd: convert nfs4_file.fi_ref from atomic_t to refcount_t fs, nfsd: convert nfs4_cntl_odstate.co_odcount from atomic_t to refcount_t fs, nfsd: convert nfs4_stid.sc_count from atomic_t to refcount_t lockd: double unregister of inetaddr notifiers nfsd4: catch some false session retries nfsd4: fix cached replies to solo SEQUENCE compounds sunrcp: make function _svc_create_xprt static SUNRPC: Fix tracepoint storage issues with svc_recv and svc_rqst_status nfsd: use ARRAY_SIZE nfsd: give out fewer session slots as limit approaches nfsd: increase DRC cache limit nfsd: remove unnecessary nofilehandle checks nfs_common: convert int to bool ...

SUNRPC: Improve ordering of transport processing

2017-11-07T21:44:03+00:00

Since it can take a while before a specific thread gets scheduled, it is better to just implement a first come first served queue mechanism. That way, if a thread is already scheduled and is idle, it can pick up the work to do from the queue. Signed-off-by: Trond Myklebust Signed-off-by: J. Bruce Fields

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

2017-11-02T10:10:55+00:00

Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart Reviewed-by: Philippe Ombredanne Reviewed-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman