nfsd: don't replace page in rq_pages if it's a continuation of last page - wireguard-linux

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author	Jeff Layton <jlayton@kernel.org>	2023-03-17 13:13:08 -0400
committer	Chuck Lever <chuck.lever@oracle.com>	2023-03-17 18:18:15 -0400
commit	27c934dd8832dd40fd34776f916dc201e18b319b (patch)
tree	c5bbb1a0062de798c42b917369cce03fc3845791 /include/uapi/linux/byteorder/ssh:/git:
parent	NFS & NFSD: Update GSS dependencies (diff)

nfsd: don't replace page in rq_pages if it's a continuation of last page

The splice read calls nfsd_splice_actor to put the pages containing file data into the svc_rqst->rq_pages array. It's possible however to get a splice result that only has a partial page at the end, if (e.g.) the filesystem hands back a short read that doesn't cover the whole page. nfsd_splice_actor will plop the partial page into its rq_pages array and return. Then later, when nfsd_splice_actor is called again, the remainder of the page may end up being filled out. At this point, nfsd_splice_actor will put the page into the array _again_ corrupting the reply. If this is done enough times, rq_next_page will overrun the array and corrupt the trailing fields -- the rq_respages and rq_next_page pointers themselves. If we've already added the page to the array in the last pass, don't add it to the array a second time when dealing with a splice continuation. This was originally handled properly in nfsd_splice_actor, but commit 91e23b1c3982 ("NFSD: Clean up nfsd_splice_actor()") removed the check for it. Fixes: 91e23b1c3982 ("NFSD: Clean up nfsd_splice_actor()") Cc: Al Viro <viro@zeniv.linux.org.uk> Reported-by: Dario Lesca <d.lesca@solinos.it> Tested-by: David Critch <dcritch@redhat.com> Link: https://bugzilla.redhat.com/show_bug.cgi?id=2150630 Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Diffstat (limited to 'include/uapi/linux/byteorder/ssh:/git:')

0 files changed, 0 insertions, 0 deletions

/* * Copyright (C) 2003 Sistina Software * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved. * * Device-Mapper dirty region log. * * This file is released under the LGPL. */ #ifndef _LINUX_DM_DIRTY_LOG #define _LINUX_DM_DIRTY_LOG #ifdef __KERNEL__ #include <linux/types.h> #include <linux/device-mapper.h> typedef sector_t region_t; struct dm_dirty_log_type; struct dm_dirty_log { struct dm_dirty_log_type *type; int (*flush_callback_fn)(struct dm_target *ti); void *context; }; struct dm_dirty_log_type { const char *name; struct module *module; /* For internal device-mapper use */ struct list_head list; int (*ctr)(struct dm_dirty_log *log, struct dm_target *ti, unsigned argc, char **argv); void (*dtr)(struct dm_dirty_log *log); /* * There are times when we don't want the log to touch * the disk. */ int (*presuspend)(struct dm_dirty_log *log); int (*postsuspend)(struct dm_dirty_log *log); int (*resume)(struct dm_dirty_log *log); /* * Retrieves the smallest size of region that the log can * deal with. */ uint32_t (*get_region_size)(struct dm_dirty_log *log); /* * A predicate to say whether a region is clean or not. * May block. */ int (*is_clean)(struct dm_dirty_log *log, region_t region); /* * Returns: 0, 1, -EWOULDBLOCK, < 0 * * A predicate function to check the area given by * [sector, sector + len) is in sync. * * If -EWOULDBLOCK is returned the state of the region is * unknown, typically this will result in a read being * passed to a daemon to deal with, since a daemon is * allowed to block. */ int (*in_sync)(struct dm_dirty_log *log, region_t region, int can_block); /* * Flush the current log state (eg, to disk). This * function may block. */ int (*flush)(struct dm_dirty_log *log); /* * Mark an area as clean or dirty. These functions may * block, though for performance reasons blocking should * be extremely rare (eg, allocating another chunk of * memory for some reason). */ void (*mark_region)(struct dm_dirty_log *log, region_t region); void (*clear_region)(struct dm_dirty_log *log, region_t region); /* * Returns: <0 (error), 0 (no region), 1 (region) * * The mirrord will need perform recovery on regions of * the mirror that are in the NOSYNC state. This * function asks the log to tell the caller about the * next region that this machine should recover. * * Do not confuse this function with 'in_sync()', one * tells you if an area is synchronised, the other * assigns recovery work. */ int (*get_resync_work)(struct dm_dirty_log *log, region_t *region); /* * This notifies the log that the resync status of a region * has changed. It also clears the region from the recovering * list (if present). */ void (*set_region_sync)(struct dm_dirty_log *log, region_t region, int in_sync); /* * Returns the number of regions that are in sync. */ region_t (*get_sync_count)(struct dm_dirty_log *log); /* * Support function for mirror status requests. */ int (*status)(struct dm_dirty_log *log, status_type_t status_type, char *result, unsigned maxlen); /* * is_remote_recovering is necessary for cluster mirroring. It provides * a way to detect recovery on another node, so we aren't writing * concurrently. This function is likely to block (when a cluster log * is used). * * Returns: 0, 1 */ int (*is_remote_recovering)(struct dm_dirty_log *log, region_t region); }; int dm_dirty_log_type_register(struct dm_dirty_log_type *type); int dm_dirty_log_type_unregister(struct dm_dirty_log_type *type); /* * Make sure you use these two functions, rather than calling * type->constructor/destructor() directly. */ struct dm_dirty_log *dm_dirty_log_create(const char *type_name, struct dm_target *ti, int (*flush_callback_fn)(struct dm_target *ti), unsigned argc, char **argv); void dm_dirty_log_destroy(struct dm_dirty_log *log); #endif /* __KERNEL__ */ #endif /* _LINUX_DM_DIRTY_LOG_H */


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