From 559d4c6a9d3b60f239493239070eb304edaea594 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Thomas=20Wei=C3=9Fschuh?= Date: Mon, 5 Aug 2024 11:39:35 +0200 Subject: [PATCH 1/2] sysctl: avoid spurious permanent empty tables MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The test if a table is a permanently empty one, inspects the address of the registered ctl_table argument. However as sysctl_mount_point is an empty array and does not occupy and space it can end up sharing an address with another object in memory. If that other object itself is a "struct ctl_table" then registering that table will fail as it's incorrectly recognized as permanently empty. Avoid this issue by adding a dummy element to the array so that is not empty anymore. Explicitly register the table with zero elements as otherwise the dummy element would be recognized as a sentinel element which would lead to a runtime warning from the sysctl core. While the issue seems not being encountered at this time, this seems mostly to be due to luck. Also a future change, constifying sysctl_mount_point and root_table, can reliably trigger this issue on clang 18. Given that empty arrays are non-standard in the first place it seems prudent to avoid them if possible. Fixes: 4a7b29f65094 ("sysctl: move sysctl type to ctl_table_header") Fixes: a35dd3a786f5 ("sysctl: drop now unnecessary out-of-bounds check") Cc: stable@vger.kernel.org Signed-off-by: Thomas Weißschuh Closes: https://lore.kernel.org/oe-lkp/202408051453.f638857e-lkp@intel.com Signed-off-by: Joel Granados --- fs/proc/proc_sysctl.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c index 9553e77c9d31..d11ebc055ce0 100644 --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c @@ -29,8 +29,13 @@ static const struct inode_operations proc_sys_inode_operations; static const struct file_operations proc_sys_dir_file_operations; static const struct inode_operations proc_sys_dir_operations; -/* Support for permanently empty directories */ -static struct ctl_table sysctl_mount_point[] = { }; +/* + * Support for permanently empty directories. + * Must be non-empty to avoid sharing an address with other tables. + */ +static struct ctl_table sysctl_mount_point[] = { + { } +}; /** * register_sysctl_mount_point() - registers a sysctl mount point @@ -42,7 +47,7 @@ static struct ctl_table sysctl_mount_point[] = { }; */ struct ctl_table_header *register_sysctl_mount_point(const char *path) { - return register_sysctl(path, sysctl_mount_point); + return register_sysctl_sz(path, sysctl_mount_point, 0); } EXPORT_SYMBOL(register_sysctl_mount_point); From 732b47db1d6c26985faca1ae5820bcfa10f6335d Mon Sep 17 00:00:00 2001 From: Joel Granados Date: Thu, 27 Jun 2024 12:29:43 +0200 Subject: [PATCH 2/2] MAINTAINERS: update email for Joel Granados Change my contact email in MAINTAINERS and .mailmap to my kernel.org. This in order to avoid cumbersome corporate email policies. Signed-off-by: Joel Granados --- .mailmap | 1 + MAINTAINERS | 2 +- 2 files changed, 2 insertions(+), 1 deletion(-) diff --git a/.mailmap b/.mailmap index 8ee01d9d7046..2da781552f78 100644 --- a/.mailmap +++ b/.mailmap @@ -311,6 +311,7 @@ Jiri Slaby Jisheng Zhang Jisheng Zhang Jishnu Prakash +Joel Granados Johan Hovold Johan Hovold John Crispin diff --git a/MAINTAINERS b/MAINTAINERS index 878dcd23b331..518798d35006 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -18334,7 +18334,7 @@ F: tools/testing/selftests/proc/ PROC SYSCTL M: Luis Chamberlain M: Kees Cook -M: Joel Granados +M: Joel Granados L: linux-kernel@vger.kernel.org L: linux-fsdevel@vger.kernel.org S: Maintained