kernel/linux.git/net/sunrpc/cache.c, branch v6.12.80

sunrpc: fix cache_request leak in cache_release

2026-03-25T10:08:47+00:00

commit 17ad31b3a43b72aec3a3d83605891e1397d0d065 upstream. When a reader's file descriptor is closed while in the middle of reading a cache_request (rp->offset != 0), cache_release() decrements the request's readers count but never checks whether it should free the request. In cache_read(), when readers drops to 0 and CACHE_PENDING is clear, the cache_request is removed from the queue and freed along with its buffer and cache_head reference. cache_release() lacks this cleanup. The only other path that frees requests with readers == 0 is cache_dequeue(), but it runs only when CACHE_PENDING transitions from set to clear. If that transition already happened while readers was still non-zero, cache_dequeue() will have skipped the request, and no subsequent call will clean it up. Add the same cleanup logic from cache_read() to cache_release(): after decrementing readers, check if it reached 0 with CACHE_PENDING clear, and if so, dequeue and free the cache_request. Reported-by: NeilBrown Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@kernel.org Signed-off-by: Jeff Layton Signed-off-by: Chuck Lever Signed-off-by: Greg Kroah-Hartman

sunrpc: suppress warnings for unused procfs functions

2025-03-07T17:25:28+00:00

[ Upstream commit 1f7a4f98c11fbeb18ed21f3b3a497e90a50ad2e0 ] There is a warning about unused variables when building with W=1 and no procfs: net/sunrpc/cache.c:1660:30: error: 'cache_flush_proc_ops' defined but not used [-Werror=unused-const-variable=] 1660 | static const struct proc_ops cache_flush_proc_ops = { | ^~~~~~~~~~~~~~~~~~~~ net/sunrpc/cache.c:1622:30: error: 'content_proc_ops' defined but not used [-Werror=unused-const-variable=] 1622 | static const struct proc_ops content_proc_ops = { | ^~~~~~~~~~~~~~~~ net/sunrpc/cache.c:1598:30: error: 'cache_channel_proc_ops' defined but not used [-Werror=unused-const-variable=] 1598 | static const struct proc_ops cache_channel_proc_ops = { | ^~~~~~~~~~~~~~~~~~~~~~ These are used inside of an #ifdef, so replacing that with an IS_ENABLED() check lets the compiler see how they are used while still dropping them during dead code elimination. Fixes: dbf847ecb631 ("knfsd: allow cache_register to return error on failure") Reviewed-by: Jeff Layton Acked-by: Chuck Lever Signed-off-by: Arnd Bergmann Signed-off-by: Anna Schumaker Signed-off-by: Sasha Levin

SUNRPC: make sure cache entry active before cache_show

2024-12-05T13:03:02+00:00

commit 2862eee078a4d2d1f584e7f24fa50dddfa5f3471 upstream. The function `c_show` was called with protection from RCU. This only ensures that `cp` will not be freed. Therefore, the reference count for `cp` can drop to zero, which will trigger a refcount use-after-free warning when `cache_get` is called. To resolve this issue, use `cache_get_rcu` to ensure that `cp` remains active. ------------[ cut here ]------------ refcount_t: addition on 0; use-after-free. WARNING: CPU: 7 PID: 822 at lib/refcount.c:25 refcount_warn_saturate+0xb1/0x120 CPU: 7 UID: 0 PID: 822 Comm: cat Not tainted 6.12.0-rc3+ #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 04/01/2014 RIP: 0010:refcount_warn_saturate+0xb1/0x120 Call Trace: c_show+0x2fc/0x380 [sunrpc] seq_read_iter+0x589/0x770 seq_read+0x1e5/0x270 proc_reg_read+0xe1/0x140 vfs_read+0x125/0x530 ksys_read+0xc1/0x160 do_syscall_64+0x5f/0x170 entry_SYSCALL_64_after_hwframe+0x76/0x7e Cc: stable@vger.kernel.org # v4.20+ Signed-off-by: Yang Erkun Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever Signed-off-by: Greg Kroah-Hartman

[tree-wide] finally take no_llseek out

2024-09-27T15:18:43+00:00

no_llseek had been defined to NULL two years ago, in commit 868941b14441 ("fs: remove no_llseek") To quote that commit, At -rc1 we'll need do a mechanical removal of no_llseek - git grep -l -w no_llseek | grep -v porting.rst | while read i; do sed -i '/\/d' $i done would do it. Unfortunately, that hadn't been done. Linus, could you do that now, so that we could finally put that thing to rest? All instances are of the form .llseek = no_llseek, so it's obviously safe. Signed-off-by: Al Viro Signed-off-by: Linus Torvalds

net/sunrpc: make use of the helper macro LIST_HEAD()

2024-09-23T19:03:13+00:00

list_head can be initialized automatically with LIST_HEAD() instead of calling INIT_LIST_HEAD(). Here we can simplify the code. Signed-off-by: Hongbo Li Signed-off-by: Anna Schumaker

treewide: use get_random_u32_below() instead of deprecated function

2022-11-18T01:15:15+00:00

This is a simple mechanical transformation done by: @@ expression E; @@ - prandom_u32_max + get_random_u32_below (E) Reviewed-by: Kees Cook Reviewed-by: Greg Kroah-Hartman Acked-by: Darrick J. Wong # for xfs Reviewed-by: SeongJae Park # for damon Reviewed-by: Jason Gunthorpe # for infiniband Reviewed-by: Russell King (Oracle) # for arm Acked-by: Ulf Hansson # for mmc Signed-off-by: Jason A. Donenfeld

treewide: use prandom_u32_max() when possible, part 1

2022-10-11T23:42:55+00:00

Rather than incurring a division or requesting too many random bytes for the given range, use the prandom_u32_max() function, which only takes the minimum required bytes from the RNG and avoids divisions. This was done mechanically with this coccinelle script: @basic@ expression E; type T; identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32"; typedef u64; @@ ( - ((T)get_random_u32() % (E)) + prandom_u32_max(E) | - ((T)get_random_u32() & ((E) - 1)) + prandom_u32_max(E * XXX_MAKE_SURE_E_IS_POW2) | - ((u64)(E) * get_random_u32() >> 32) + prandom_u32_max(E) | - ((T)get_random_u32() & ~PAGE_MASK) + prandom_u32_max(PAGE_SIZE) ) @multi_line@ identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32"; identifier RAND; expression E; @@ - RAND = get_random_u32(); ... when != RAND - RAND %= (E); + RAND = prandom_u32_max(E); // Find a potential literal @literal_mask@ expression LITERAL; type T; identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32"; position p; @@ ((T)get_random_u32()@p & (LITERAL)) // Add one to the literal. @script:python add_one@ literal << literal_mask.LITERAL; RESULT; @@ value = None if literal.startswith('0x'): value = int(literal, 16) elif literal[0] in '123456789': value = int(literal, 10) if value is None: print("I don't know how to handle %s" % (literal)) cocci.include_match(False) elif value == 2**32 - 1 or value == 2**31 - 1 or value == 2**24 - 1 or value == 2**16 - 1 or value == 2**8 - 1: print("Skipping 0x%x for cleanup elsewhere" % (value)) cocci.include_match(False) elif value & (value + 1) != 0: print("Skipping 0x%x because it's not a power of two minus one" % (value)) cocci.include_match(False) elif literal.startswith('0x'): coccinelle.RESULT = cocci.make_expr("0x%x" % (value + 1)) else: coccinelle.RESULT = cocci.make_expr("%d" % (value + 1)) // Replace the literal mask with the calculated result. @plus_one@ expression literal_mask.LITERAL; position literal_mask.p; expression add_one.RESULT; identifier FUNC; @@ - (FUNC()@p & (LITERAL)) + prandom_u32_max(RESULT) @collapse_ret@ type T; identifier VAR; expression E; @@ { - T VAR; - VAR = (E); - return VAR; + return E; } @drop_var@ type T; identifier VAR; @@ { - T VAR; ... when != VAR } Reviewed-by: Greg Kroah-Hartman Reviewed-by: Kees Cook Reviewed-by: Yury Norov Reviewed-by: KP Singh Reviewed-by: Jan Kara # for ext4 and sbitmap Reviewed-by: Christoph Böhmwalder # for drbd Acked-by: Jakub Kicinski Acked-by: Heiko Carstens # for s390 Acked-by: Ulf Hansson # for mmc Acked-by: Darrick J. Wong # for xfs Signed-off-by: Jason A. Donenfeld

SUNRPC: Cache deferral injection

2022-05-19T16:25:38+00:00

Cache deferral injection stress-tests the cache deferral logic as well as upper layer protocol deferred request handlers. This facility is for developers and professional testers to ensure coverage of the rqst deferral code paths. To date, we haven't had an adequate way to ensure these code paths are covered during testing, short of temporary code changes to force their use. A file called /sys/kernel/debug/fail_sunrpc/ignore-cache-wait enables administrators to disable cache deferral injection while allowing other types of sunrpc errors to be injected. The default setting is that cache deferral injection is enabled (ignore=false). To enable support for cache deferral injection, CONFIG_FAULT_INJECTION, CONFIG_FAULT_INJECTION_DEBUG_FS, and CONFIG_SUNRPC_DEBUG must all be set to "Y". Signed-off-by: Chuck Lever

proc: remove PDE_DATA() completely

2022-01-22T06:33:37+00:00

Remove PDE_DATA() completely and replace it with pde_data(). [akpm@linux-foundation.org: fix naming clash in drivers/nubus/proc.c] [akpm@linux-foundation.org: now fix it properly] Link: https://lkml.kernel.org/r/20211124081956.87711-2-songmuchun@bytedance.com Signed-off-by: Muchun Song Acked-by: Christian Brauner Cc: Alexey Dobriyan Cc: Alexey Gladkov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

SUNRPC: improve error response to over-size gss credential

2021-09-03T17:38:11+00:00

When the NFS server receives a large gss (kerberos) credential and tries to pass it up to rpc.svcgssd (which is deprecated), it triggers an infinite loop in cache_read(). cache_request() always returns -EAGAIN, and this causes a "goto again". This patch: - changes the error to -E2BIG to avoid the infinite loop, and - generates a WARN_ONCE when rsi_request first sees an over-sized credential. The warning suggests switching to gssproxy. Link: https://bugzilla.kernel.org/show_bug.cgi?id=196583 Signed-off-by: NeilBrown Signed-off-by: Chuck Lever