user/sven/linux.git/kernel/ucount.c, branch v6.12.4

signal: restore the override_rlimit logic

2024-11-07T22:14:59Z

Prior to commit d64696905554 ("Reimplement RLIMIT_SIGPENDING on top of ucounts") UCOUNT_RLIMIT_SIGPENDING rlimit was not enforced for a class of signals. However now it's enforced unconditionally, even if override_rlimit is set. This behavior change caused production issues. For example, if the limit is reached and a process receives a SIGSEGV signal, sigqueue_alloc fails to allocate the necessary resources for the signal delivery, preventing the signal from being delivered with siginfo. This prevents the process from correctly identifying the fault address and handling the error. From the user-space perspective, applications are unaware that the limit has been reached and that the siginfo is effectively 'corrupted'. This can lead to unpredictable behavior and crashes, as we observed with java applications. Fix this by passing override_rlimit into inc_rlimit_get_ucounts() and skip the comparison to max there if override_rlimit is set. This effectively restores the old behavior. Link: https://lkml.kernel.org/r/20241104195419.3962584-1-roman.gushchin@linux.dev Fixes: d64696905554 ("Reimplement RLIMIT_SIGPENDING on top of ucounts") Signed-off-by: Roman Gushchin Co-developed-by: Andrei Vagin Signed-off-by: Andrei Vagin Acked-by: Oleg Nesterov Acked-by: Alexey Gladkov Cc: Kees Cook Cc: "Eric W. Biederman" Cc: Signed-off-by: Andrew Morton

ucounts: fix counter leak in inc_rlimit_get_ucounts()

2024-11-07T22:14:59Z

The inc_rlimit_get_ucounts() increments the specified rlimit counter and then checks its limit. If the value exceeds the limit, the function returns an error without decrementing the counter. Link: https://lkml.kernel.org/r/20241101191940.3211128-1-roman.gushchin@linux.dev Fixes: 15bc01effefe ("ucounts: Fix signal ucount refcounting") Signed-off-by: Andrei Vagin Co-developed-by: Roman Gushchin Signed-off-by: Roman Gushchin Tested-by: Roman Gushchin Acked-by: Alexey Gladkov Cc: Kees Cook Cc: Andrei Vagin Cc: "Eric W. Biederman" Cc: Alexey Gladkov Cc: Oleg Nesterov Cc: Signed-off-by: Andrew Morton

Merge tag 'sysctl-6.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl

2024-05-18T00:31:24Z

Pull sysctl updates from Joel Granados: - Remove sentinel elements from ctl_table structs in kernel/* Removing sentinels in ctl_table arrays reduces the build time size and runtime memory consumed by ~64 bytes per array. Removals for net/, io_uring/, mm/, ipc/ and security/ are set to go into mainline through their respective subsystems making the next release the most likely place where the final series that removes the check for proc_name == NULL will land. This adds to removals already in arch/, drivers/ and fs/. - Adjust ctl_table definitions and references to allow constification - Remove unused ctl_table function arguments - Move non-const elements from ctl_table to ctl_table_header - Make ctl_table pointers const in ctl_table_root structure Making the static ctl_table structs const will increase safety by keeping the pointers to proc_handler functions in .rodata. Though no ctl_tables where made const in this PR, the ground work for making that possible has started with these changes sent by Thomas Weißschuh. * tag 'sysctl-6.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl: sysctl: drop now unnecessary out-of-bounds check sysctl: move sysctl type to ctl_table_header sysctl: drop sysctl_is_perm_empty_ctl_table sysctl: treewide: constify argument ctl_table_root::permissions(table) sysctl: treewide: drop unused argument ctl_table_root::set_ownership(table) bpf: Remove the now superfluous sentinel elements from ctl_table array delayacct: Remove the now superfluous sentinel elements from ctl_table array kprobes: Remove the now superfluous sentinel elements from ctl_table array printk: Remove the now superfluous sentinel elements from ctl_table array scheduler: Remove the now superfluous sentinel elements from ctl_table array seccomp: Remove the now superfluous sentinel elements from ctl_table array timekeeping: Remove the now superfluous sentinel elements from ctl_table array ftrace: Remove the now superfluous sentinel elements from ctl_table array umh: Remove the now superfluous sentinel elements from ctl_table array kernel misc: Remove the now superfluous sentinel elements from ctl_table array

sysctl: treewide: constify argument ctl_table_root::permissions(table)

2024-04-24T07:43:54Z

The permissions callback should not modify the ctl_table. Enforce this expectation via the typesystem. This is a step to put "struct ctl_table" into .rodata throughout the kernel. The patch was created with the following coccinelle script: @@ identifier func, head, ctl; @@ int func( struct ctl_table_header *head, - struct ctl_table *ctl) + const struct ctl_table *ctl) { ... } (insert_entry() from fs/proc/proc_sysctl.c is a false-positive) No additional occurrences of '.permissions =' were found after a tree-wide search for places missed by the conccinelle script. Reviewed-by: Joel Granados Signed-off-by: Thomas Weißschuh Signed-off-by: Joel Granados

kernel misc: Remove the now superfluous sentinel elements from ctl_table array

2024-04-24T07:43:53Z

This commit comes at the tail end of a greater effort to remove the empty elements at the end of the ctl_table arrays (sentinels) which will reduce the overall build time size of the kernel and run time memory bloat by ~64 bytes per sentinel (further information Link : https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/) Remove the sentinel from ctl_table arrays. Reduce by one the values used to compare the size of the adjusted arrays. Signed-off-by: Joel Granados

sysctl: treewide: constify ctl_table_header::ctl_table_arg

2024-04-22T07:56:31Z

To be able to constify instances of struct ctl_tables it is necessary to remove ways through which non-const versions are exposed from the sysctl core. One of these is the ctl_table_arg member of struct ctl_table_header. Constify this reference as a prerequisite for the full constification of struct ctl_table instances. No functional change. Signed-off-by: Thomas Weißschuh Reviewed-by: Kees Cook Signed-off-by: David S. Miller

sysctl: Add size to register_sysctl

2023-08-15T22:26:17Z

This commit adds table_size to register_sysctl in preparation for the removal of the sentinel elements in the ctl_table arrays (last empty markers). And though we do *not* remove any sentinels in this commit, we set things up by either passing the table_size explicitly or using ARRAY_SIZE on the ctl_table arrays. We replace the register_syctl function with a macro that will add the ARRAY_SIZE to the new register_sysctl_sz function. In this way the callers that are already using an array of ctl_table structs do not change. For the callers that pass a ctl_table array pointer, we pass the table_size to register_sysctl_sz instead of the macro. Signed-off-by: Joel Granados Suggested-by: Greg Kroah-Hartman Signed-off-by: Luis Chamberlain

sysctl: Add a size arg to __register_sysctl_table

2023-08-15T22:26:17Z

We make these changes in order to prepare __register_sysctl_table and its callers for when we remove the sentinel element (empty element at the end of ctl_table arrays). We don't actually remove any sentinels in this commit, but we *do* make sure to use ARRAY_SIZE so the table_size is available when the removal occurs. We add a table_size argument to __register_sysctl_table and adjust callers, all of which pass ctl_table pointers and need an explicit call to ARRAY_SIZE. We implement a size calculation in register_net_sysctl in order to forward the size of the array pointer received from the network register calls. The new table_size argument does not yet have any effect in the init_header call which is still dependent on the sentinel's presence. table_size *does* however drive the `kzalloc` allocation in __register_sysctl_table with no adverse effects as the allocated memory is either one element greater than the calculated ctl_table array (for the calls in ipc_sysctl.c, mq_sysctl.c and ucount.c) or the exact size of the calculated ctl_table array (for the call from sysctl_net.c and register_sysctl). This approach will allows us to "just" remove the sentinel without further changes to __register_sysctl_table as table_size will represent the exact size for all the callers at that point. Signed-off-by: Joel Granados Signed-off-by: Luis Chamberlain

ucounts: Split rlimit and ucount values and max values

2022-05-18T23:24:57Z

Since the semantics of maximum rlimit values are different, it would be better not to mix ucount and rlimit values. This will prevent the error of using inc_count/dec_ucount for rlimit parameters. This patch also renames the functions to emphasize the lack of connection between rlimit and ucount. v3: - Fix BUG:KASAN:use-after-free_in_dec_ucount. v2: - Fix the array-index-out-of-bounds that was found by the lkp project. Reported-by: kernel test robot Signed-off-by: Alexey Gladkov Signed-off-by: Eric W. Biederman Link: https://lkml.kernel.org/r/20220518171730.l65lmnnjtnxnftpq@example.org Signed-off-by: Eric W. Biederman

ucounts: Handle wrapping in is_ucounts_overlimit

2022-02-17T15:11:57Z

While examining is_ucounts_overlimit and reading the various messages I realized that is_ucounts_overlimit fails to deal with counts that may have wrapped. Being wrapped should be a transitory state for counts and they should never be wrapped for long, but it can happen so handle it. Cc: stable@vger.kernel.org Fixes: 21d1c5e386bc ("Reimplement RLIMIT_NPROC on top of ucounts") Link: https://lkml.kernel.org/r/20220216155832.680775-5-ebiederm@xmission.com Reviewed-by: Shuah Khan Signed-off-by: "Eric W. Biederman"