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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Jonathan Corbet , Shuah Khan , Randy Dunlap , David Ahern , Ido Schimmel , Thomas Gleixner , Petr Pavlu , Kuniyuki Iwashima , Fernando Fernandez Mancera , Willem de Bruijn , Maoyi Xie , Gerd Rausch , Zhan Xusheng , Oleg Nesterov , Chia-Yu Chang , Yung Chih Su , Wyatt Feng , Hannes Frederic Sowa , Flavio Leitner , Petr Mladek , "Paul E. McKenney" , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH net v2 5/5] net: restrict message_cost and message_burst to non-negative values Date: Tue, 27 Oct 2026 18:45:33 +0800 Message-ID: <20261027104701.296240-6-jiayuan.chen@linux.dev> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20261027104701.296240-1-jiayuan.chen@linux.dev> References: <20261027104701.296240-1-jiayuan.chen@linux.dev> X-Mailing-List: netdev@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit net.core.message_cost and net.core.message_burst feed the interval and burst of net_ratelimit_state, but neither rejects negative values: message_burst uses plain proc_dointvec, and message_cost uses proc_dointvec_jiffies, which happily stores -1 second as -HZ jiffies. Since commit a940d145cc38 ("ratelimit: Warn if ->interval or ->burst are negative"), ___ratelimit() splats on such values, so the next net_ratelimit() caller warns, e.g. a martian source log: Negative interval (-250) or burst (10): Uninitialized ratelimit_state structure? WARNING: lib/ratelimit.c:43 at ___ratelimit+0x56e/0x960, CPU#1: ping/3218 RIP: 0010:___ratelimit+0x578/0x960 Call Trace: net_ratelimit+0x1c/0x30 ip_handle_martian_source+0x1bb/0x340 ip_route_input_slow+0x1057/0x3650 ip_route_input_noref+0x104/0x260 arp_process+0x109b/0x2510 arp_rcv+0x381/0x460 __netif_receive_skb_one_core+0x173/0x1c0 __netif_receive_skb+0x21/0x150 process_backlog+0x37e/0x1200 __napi_poll.constprop.0+0xa5/0x5e0 net_rx_action+0x4c0/0xf70 handle_softirqs+0x204/0x9b0 __do_softirq+0x10/0x18 do_softirq.part.0+0x49/0xd0 Negative values never meant anything here: 0 already expresses both "no limit" (interval) and "suppress everything" (burst). Reject them at write time. message_burst can simply use proc_dointvec_minmax with extra1 = 0. proc_dointvec_jiffies has no minmax variant, so add proc_dointvec_jiffies_minmax(), mirroring proc_dointvec_ms_jiffies_minmax(), and use it for message_cost with extra1 = 0. Note that like the ms variant, extra1/extra2 are compared against the converted jiffies value. Fixes: a940d145cc38 ("ratelimit: Warn if ->interval or ->burst are negative") Cc: stable@vger.kernel.org Suggested-by: Joel Granados Signed-off-by: Jiayuan Chen --- include/linux/jiffies.h | 2 ++ kernel/time/jiffies.c | 40 ++++++++++++++++++++++++++++++++++++++ net/core/sysctl_net_core.c | 6 ++++-- 3 files changed, 46 insertions(+), 2 deletions(-) diff --git a/include/linux/jiffies.h b/include/linux/jiffies.h index bbd57061802cd..de12920f8e94b 100644 --- a/include/linux/jiffies.h +++ b/include/linux/jiffies.h @@ -646,6 +646,8 @@ extern unsigned long nsecs_to_jiffies(u64 n); struct ctl_table; int proc_dointvec_jiffies(const struct ctl_table *table, int dir, void *buffer, size_t *lenp, loff_t *ppos); +int proc_dointvec_jiffies_minmax(const struct ctl_table *table, int dir, + void *buffer, size_t *lenp, loff_t *ppos); int proc_dointvec_ms_jiffies_minmax(const struct ctl_table *table, int dir, void *buffer, size_t *lenp, loff_t *ppos); int proc_dointvec_userhz_jiffies(const struct ctl_table *table, int dir, diff --git a/kernel/time/jiffies.c b/kernel/time/jiffies.c index 9b3487d40cd6a..22a70caa58bc1 100644 --- a/kernel/time/jiffies.c +++ b/kernel/time/jiffies.c @@ -165,6 +165,14 @@ static int do_proc_int_conv_jiffies(bool *negp, ulong *u_ptr, int *k_ptr, sysctl_u2k_int_conv_hz, sysctl_k2u_int_conv_hz); } +static int do_proc_int_conv_jiffies_minmax(bool *negp, ulong *u_ptr, + int *k_ptr, int dir, + const struct ctl_table *tbl) +{ + return proc_int_conv(negp, u_ptr, k_ptr, dir, tbl, true, + sysctl_u2k_int_conv_hz, sysctl_k2u_int_conv_hz); +} + static int do_proc_int_conv_userhz_jiffies(bool *negp, ulong *u_ptr, int *k_ptr, int dir, const struct ctl_table *tbl) @@ -213,6 +221,13 @@ static int do_proc_int_conv_jiffies(bool *negp, ulong *u_ptr, int *k_ptr, return -ENOSYS; } +static int do_proc_int_conv_jiffies_minmax(bool *negp, ulong *u_ptr, + int *k_ptr, int dir, + const struct ctl_table *tbl) +{ + return -ENOSYS; +} + static int do_proc_int_conv_userhz_jiffies(bool *negp, ulong *u_ptr, int *k_ptr, int dir, const struct ctl_table *tbl) @@ -263,6 +278,31 @@ int proc_dointvec_jiffies(const struct ctl_table *table, int dir, } EXPORT_SYMBOL(proc_dointvec_jiffies); +/** + * proc_dointvec_jiffies_minmax - read a vector of integers as seconds with min/max values + * @table: the sysctl table + * @dir: %TRUE if this is a write to the sysctl file + * @buffer: the user buffer + * @lenp: the size of the user buffer + * @ppos: file position + * + * Reads/writes up to table->maxlen/sizeof(unsigned int) integer + * values from/to the user buffer, treated as an ASCII string. + * The values read are assumed to be in seconds, and are converted into + * jiffies. The converted values are checked against the optional + * table->extra1 (min) and table->extra2 (max) bounds, in jiffies; + * a value outside the range is rejected with -EINVAL. + * + * Returns 0 on success. + */ +int proc_dointvec_jiffies_minmax(const struct ctl_table *table, int dir, + void *buffer, size_t *lenp, loff_t *ppos) +{ + return proc_dointvec_conv(table, dir, buffer, lenp, ppos, + do_proc_int_conv_jiffies_minmax); +} +EXPORT_SYMBOL(proc_dointvec_jiffies_minmax); + /** * proc_dointvec_userhz_jiffies - read a vector of integers as 1/USER_HZ seconds * @table: the sysctl table diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c index 473c162736d69..9226b96f2e89b 100644 --- a/net/core/sysctl_net_core.c +++ b/net/core/sysctl_net_core.c @@ -544,14 +544,16 @@ static struct ctl_table net_core_table[] = { .data = &net_ratelimit_state.interval, .maxlen = sizeof(int), .mode = 0644, - .proc_handler = proc_dointvec_jiffies, + .proc_handler = proc_dointvec_jiffies_minmax, + .extra1 = SYSCTL_ZERO, }, { .procname = "message_burst", .data = &net_ratelimit_state.burst, .maxlen = sizeof(int), .mode = 0644, - .proc_handler = proc_dointvec, + .proc_handler = proc_dointvec_minmax, + .extra1 = SYSCTL_ZERO, }, #ifdef CONFIG_RPS { -- 2.43.0