From 5cac98dd06bc43a7baab3523184f70fd359e9f35 Mon Sep 17 00:00:00 2001 From: Anton Blanchard Date: Sun, 27 Nov 2011 21:14:46 +0000 Subject: [PATCH] net: Fix corruption in /proc/*/net/dev_mcast I just hit this during my testing. Isn't there another bug lurking? BUG kmalloc-8: Redzone overwritten INFO: 0xc0000000de9dec48-0xc0000000de9dec4b. First byte 0x0 instead of 0xcc INFO: Allocated in .__seq_open_private+0x30/0xa0 age=0 cpu=5 pid=3896 .__kmalloc+0x1e0/0x2d0 .__seq_open_private+0x30/0xa0 .seq_open_net+0x60/0xe0 .dev_mc_seq_open+0x4c/0x70 .proc_reg_open+0xd8/0x260 .__dentry_open.clone.11+0x2b8/0x400 .do_last+0xf4/0x950 .path_openat+0xf8/0x480 .do_filp_open+0x48/0xc0 .do_sys_open+0x140/0x250 syscall_exit+0x0/0x40 dev_mc_seq_ops uses dev_seq_start/next/stop but only allocates sizeof(struct seq_net_private) of private data, whereas it expects sizeof(struct dev_iter_state): struct dev_iter_state { struct seq_net_private p; unsigned int pos; /* bucket << BUCKET_SPACE + offset */ }; Create dev_seq_open_ops and use it so we don't have to expose struct dev_iter_state. [ Problem added by commit f04565ddf52e4 (dev: use name hash for dev_seq_ops) -Eric ] Signed-off-by: Anton Blanchard Acked-by: Eric Dumazet Signed-off-by: David S. Miller --- include/linux/netdevice.h | 2 ++ net/core/dev.c | 6 ++++++ net/core/dev_addr_lists.c | 3 +-- 3 files changed, 9 insertions(+), 2 deletions(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index cbeb5867cff7..a82ad4dd306a 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -2536,6 +2536,8 @@ extern void net_disable_timestamp(void); extern void *dev_seq_start(struct seq_file *seq, loff_t *pos); extern void *dev_seq_next(struct seq_file *seq, void *v, loff_t *pos); extern void dev_seq_stop(struct seq_file *seq, void *v); +extern int dev_seq_open_ops(struct inode *inode, struct file *file, + const struct seq_operations *ops); #endif extern int netdev_class_create_file(struct class_attribute *class_attr); diff --git a/net/core/dev.c b/net/core/dev.c index 6ba50a1e404c..1482eea0bbf0 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -4282,6 +4282,12 @@ static int dev_seq_open(struct inode *inode, struct file *file) sizeof(struct dev_iter_state)); } +int dev_seq_open_ops(struct inode *inode, struct file *file, + const struct seq_operations *ops) +{ + return seq_open_net(inode, file, ops, sizeof(struct dev_iter_state)); +} + static const struct file_operations dev_seq_fops = { .owner = THIS_MODULE, .open = dev_seq_open, diff --git a/net/core/dev_addr_lists.c b/net/core/dev_addr_lists.c index 277faef9148d..febba516db62 100644 --- a/net/core/dev_addr_lists.c +++ b/net/core/dev_addr_lists.c @@ -696,8 +696,7 @@ static const struct seq_operations dev_mc_seq_ops = { static int dev_mc_seq_open(struct inode *inode, struct file *file) { - return seq_open_net(inode, file, &dev_mc_seq_ops, - sizeof(struct seq_net_private)); + return dev_seq_open_ops(inode, file, &dev_mc_seq_ops); } static const struct file_operations dev_mc_seq_fops = { -- 2.20.1