From e609a6b85182f8a479d265839d3ff9aad2e67b18 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Thu, 9 Nov 2017 13:38:18 -0800 Subject: sysctl: add register_sysctl() dummy helper register_sysctl() has been around for five years with commit fea478d4101a ("sysctl: Add register_sysctl for normal sysctl users") but now that arm64 started using it, I ran into a compile error: arch/arm64/kernel/armv8_deprecated.c: In function 'register_insn_emulation_sysctl': arch/arm64/kernel/armv8_deprecated.c:257:2: error: implicit declaration of function 'register_sysctl' This adds a inline function like we already have for register_sysctl_paths() and register_sysctl_table(). Link: http://lkml.kernel.org/r/20171106133700.558647-1-arnd@arndb.de Fixes: 38b9aeb32fa7 ("arm64: Port deprecated instruction emulation to new sysctl interface") Signed-off-by: Arnd Bergmann Reviewed-by: Dave Martin Acked-by: Kees Cook Acked-by: Will Deacon Cc: Catalin Marinas Cc: "Luis R. Rodriguez" Cc: Alex Benne Cc: Arnd Bergmann Cc: "Eric W. Biederman" Cc: Thomas Gleixner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/sysctl.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include/linux/sysctl.h') diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h index 74f91eefeccf..b769ecfcc3bd 100644 --- a/include/linux/sysctl.h +++ b/include/linux/sysctl.h @@ -213,6 +213,11 @@ static inline struct ctl_table_header *register_sysctl_paths( return NULL; } +static inline struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table) +{ + return NULL; +} + static inline void unregister_sysctl_table(struct ctl_table_header * table) { } -- cgit v1.2.3 From 7a8d181949fb2c16be00f8cdb354794a30e46b39 Mon Sep 17 00:00:00 2001 From: Joe Lawrence Date: Fri, 17 Nov 2017 15:29:24 -0800 Subject: pipe: add proc_dopipe_max_size() to safely assign pipe_max_size pipe_max_size is assigned directly via procfs sysctl: static struct ctl_table fs_table[] = { ... { .procname = "pipe-max-size", .data = &pipe_max_size, .maxlen = sizeof(int), .mode = 0644, .proc_handler = &pipe_proc_fn, .extra1 = &pipe_min_size, }, ... int pipe_proc_fn(struct ctl_table *table, int write, void __user *buf, size_t *lenp, loff_t *ppos) { ... ret = proc_dointvec_minmax(table, write, buf, lenp, ppos) ... and then later rounded in-place a few statements later: ... pipe_max_size = round_pipe_size(pipe_max_size); ... This leaves a window of time between initial assignment and rounding that may be visible to other threads. (For example, one thread sets a non-rounded value to pipe_max_size while another reads its value.) Similar reads of pipe_max_size are potentially racy: pipe.c :: alloc_pipe_info() pipe.c :: pipe_set_size() Add a new proc_dopipe_max_size() that consolidates reading the new value from the user buffer, verifying bounds, and calling round_pipe_size() with a single assignment to pipe_max_size. Link: http://lkml.kernel.org/r/1507658689-11669-4-git-send-email-joe.lawrence@redhat.com Signed-off-by: Joe Lawrence Reported-by: Mikulas Patocka Reviewed-by: Mikulas Patocka Cc: Al Viro Cc: Jens Axboe Cc: Michael Kerrisk Cc: Randy Dunlap Cc: Josh Poimboeuf Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/sysctl.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/linux/sysctl.h') diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h index b769ecfcc3bd..992bc9948232 100644 --- a/include/linux/sysctl.h +++ b/include/linux/sysctl.h @@ -51,6 +51,9 @@ extern int proc_dointvec_minmax(struct ctl_table *, int, extern int proc_douintvec_minmax(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos); +extern int proc_dopipe_max_size(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, + loff_t *ppos); extern int proc_dointvec_jiffies(struct ctl_table *, int, void __user *, size_t *, loff_t *); extern int proc_dointvec_userhz_jiffies(struct ctl_table *, int, -- cgit v1.2.3 From 319e0a21bb7823abbb4818fe2724e572bbac77a2 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Tue, 6 Feb 2018 15:41:49 -0800 Subject: pipe, sysctl: remove pipe_proc_fn() pipe_proc_fn() is no longer needed, as it only calls through to proc_dopipe_max_size(). Just put proc_dopipe_max_size() in the ctl_table entry directly, and remove the unneeded EXPORT_SYMBOL() and the ENOSYS stub for it. (The reason the ENOSYS stub isn't needed is that the pipe-max-size ctl_table entry is located directly in 'kern_table' rather than being registered separately. Therefore, the entry is already only defined when the kernel is built with sysctl support.) Link: http://lkml.kernel.org/r/20180111052902.14409-3-ebiggers3@gmail.com Signed-off-by: Eric Biggers Acked-by: Kees Cook Acked-by: Joe Lawrence Cc: Alexander Viro Cc: "Luis R . Rodriguez" Cc: Michael Kerrisk Cc: Mikulas Patocka Cc: Willy Tarreau Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/sysctl.h | 3 --- 1 file changed, 3 deletions(-) (limited to 'include/linux/sysctl.h') diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h index 992bc9948232..b769ecfcc3bd 100644 --- a/include/linux/sysctl.h +++ b/include/linux/sysctl.h @@ -51,9 +51,6 @@ extern int proc_dointvec_minmax(struct ctl_table *, int, extern int proc_douintvec_minmax(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos); -extern int proc_dopipe_max_size(struct ctl_table *table, int write, - void __user *buffer, size_t *lenp, - loff_t *ppos); extern int proc_dointvec_jiffies(struct ctl_table *, int, void __user *, size_t *, loff_t *); extern int proc_dointvec_userhz_jiffies(struct ctl_table *, int, -- cgit v1.2.3