Implement ->proc_write_buf() for the files in /proc/fs/cifs so procfs copies in what is written before it pins the entry, and parse what was written from that copy. Writes larger than PAGE_SIZE - 1 bytes fail with -EINVAL now, SecurityFlags never took more than 11 bytes. Empty writes to cifsFYI and dfscache fail with -EINVAL too, they looked at a byte that wasn't written before. kstrtoint_from_user() looked at the first 34 bytes of a write to cifs_debug_dirs and the smbdirect files, now the whole write is parsed.
Signed-off-by: Christian Brauner (Amutable) <[email protected]> --- fs/smb/client/cifs_debug.c | 62 +++++++++++++++++++--------------------------- fs/smb/client/dfs_cache.c | 13 +++------- 2 files changed, 29 insertions(+), 46 deletions(-) diff --git a/fs/smb/client/cifs_debug.c b/fs/smb/client/cifs_debug.c index 664072ab3342..fb1323bf44c7 100644 --- a/fs/smb/client/cifs_debug.c +++ b/fs/smb/client/cifs_debug.c @@ -359,12 +359,12 @@ static int cifs_debug_dirs_proc_show(struct seq_file *m, void *v) #ifdef CONFIG_CIFS_DEBUG /* Drop all cached directory entries across all CIFS mounts. */ -static ssize_t cifs_debug_dirs_proc_write(struct file *file, const char __user *buffer, +static ssize_t cifs_debug_dirs_proc_write(struct file *file, char *buffer, size_t count, loff_t *ppos) { int rc, v; - rc = kstrtoint_from_user(buffer, count, 10, &v); + rc = kstrtoint(buffer, 10, &v); if (rc) return rc; @@ -390,7 +390,7 @@ static ssize_t cifs_debug_dirs_proc_write(struct file *file, const char __user * static const struct proc_ops cifs_debug_dirs_proc_ops = { .proc_show = cifs_debug_dirs_proc_show, - .proc_write = cifs_debug_dirs_proc_write, + .proc_write_buf = cifs_debug_dirs_proc_write, }; #endif /* CONFIG_CIFS_DEBUG */ @@ -713,8 +713,8 @@ static int cifs_debug_data_proc_show(struct seq_file *m, void *v) return 0; } -static ssize_t cifs_stats_proc_write(struct file *file, - const char __user *buffer, size_t count, loff_t *ppos) +static ssize_t cifs_stats_proc_write(struct file *file, char *buffer, + size_t count, loff_t *ppos) { bool bv; int rc; @@ -722,7 +722,7 @@ static ssize_t cifs_stats_proc_write(struct file *file, struct cifs_ses *ses; struct cifs_tcon *tcon; - rc = kstrtobool_from_user(buffer, count, &bv); + rc = kstrtobool(buffer, &bv); if (rc == 0) { #ifdef CONFIG_CIFS_STATS2 int i; @@ -854,16 +854,16 @@ static int cifs_stats_proc_show(struct seq_file *m, void *v) static const struct proc_ops cifs_stats_proc_ops = { .proc_show = cifs_stats_proc_show, - .proc_write = cifs_stats_proc_write, + .proc_write_buf = cifs_stats_proc_write, }; #ifdef CONFIG_CIFS_SMB_DIRECT #define PROC_FILE_DEFINE(name) \ -static ssize_t name##_write(struct file *file, const char __user *buffer, \ +static ssize_t name##_write(struct file *file, char *buffer, \ size_t count, loff_t *ppos) \ { \ int rc; \ - rc = kstrtoint_from_user(buffer, count, 10, &name); \ + rc = kstrtoint(buffer, 10, &name); \ if (rc) \ return rc; \ return count; \ @@ -876,7 +876,7 @@ static int name##_proc_show(struct seq_file *m, void *v) \ \ static const struct proc_ops cifs_##name##_proc_fops = { \ .proc_show = name##_proc_show, \ - .proc_write = name##_write, \ + .proc_write_buf = name##_write, \ } PROC_FILE_DEFINE(rdma_readwrite_threshold); @@ -990,16 +990,12 @@ static int cifsFYI_proc_show(struct seq_file *m, void *v) return 0; } -static ssize_t cifsFYI_proc_write(struct file *file, const char __user *buffer, +static ssize_t cifsFYI_proc_write(struct file *file, char *buffer, size_t count, loff_t *ppos) { - char c[2] = { '\0' }; + char c[2] = { buffer[0] }; bool bv; - int rc; - rc = get_user(c[0], buffer); - if (rc) - return rc; if (kstrtobool(c, &bv) == 0) cifsFYI = bv; else if ((c[0] > '1') && (c[0] <= '9')) @@ -1012,7 +1008,7 @@ static ssize_t cifsFYI_proc_write(struct file *file, const char __user *buffer, static const struct proc_ops cifsFYI_proc_ops = { .proc_show = cifsFYI_proc_show, - .proc_write = cifsFYI_proc_write, + .proc_write_buf = cifsFYI_proc_write, }; static int cifs_linux_ext_proc_show(struct seq_file *m, void *v) @@ -1021,12 +1017,12 @@ static int cifs_linux_ext_proc_show(struct seq_file *m, void *v) return 0; } -static ssize_t cifs_linux_ext_proc_write(struct file *file, - const char __user *buffer, size_t count, loff_t *ppos) +static ssize_t cifs_linux_ext_proc_write(struct file *file, char *buffer, + size_t count, loff_t *ppos) { int rc; - rc = kstrtobool_from_user(buffer, count, &linuxExtEnabled); + rc = kstrtobool(buffer, &linuxExtEnabled); if (rc) return rc; @@ -1035,7 +1031,7 @@ static ssize_t cifs_linux_ext_proc_write(struct file *file, static const struct proc_ops cifs_linux_ext_proc_ops = { .proc_show = cifs_linux_ext_proc_show, - .proc_write = cifs_linux_ext_proc_write, + .proc_write_buf = cifs_linux_ext_proc_write, }; static int cifs_lookup_cache_proc_show(struct seq_file *m, void *v) @@ -1044,12 +1040,12 @@ static int cifs_lookup_cache_proc_show(struct seq_file *m, void *v) return 0; } -static ssize_t cifs_lookup_cache_proc_write(struct file *file, - const char __user *buffer, size_t count, loff_t *ppos) +static ssize_t cifs_lookup_cache_proc_write(struct file *file, char *buffer, + size_t count, loff_t *ppos) { int rc; - rc = kstrtobool_from_user(buffer, count, &lookupCacheEnabled); + rc = kstrtobool(buffer, &lookupCacheEnabled); if (rc) return rc; @@ -1058,7 +1054,7 @@ static ssize_t cifs_lookup_cache_proc_write(struct file *file, static const struct proc_ops cifs_lookup_cache_proc_ops = { .proc_show = cifs_lookup_cache_proc_show, - .proc_write = cifs_lookup_cache_proc_write, + .proc_write_buf = cifs_lookup_cache_proc_write, }; static int traceSMB_proc_show(struct seq_file *m, void *v) @@ -1067,12 +1063,12 @@ static int traceSMB_proc_show(struct seq_file *m, void *v) return 0; } -static ssize_t traceSMB_proc_write(struct file *file, const char __user *buffer, +static ssize_t traceSMB_proc_write(struct file *file, char *buffer, size_t count, loff_t *ppos) { int rc; - rc = kstrtobool_from_user(buffer, count, &traceSMB); + rc = kstrtobool(buffer, &traceSMB); if (rc) return rc; @@ -1081,7 +1077,7 @@ static ssize_t traceSMB_proc_write(struct file *file, const char __user *buffer, static const struct proc_ops traceSMB_proc_ops = { .proc_show = traceSMB_proc_show, - .proc_write = traceSMB_proc_write, + .proc_write_buf = traceSMB_proc_write, }; static int cifs_security_flags_proc_show(struct seq_file *m, void *v) @@ -1111,21 +1107,15 @@ cifs_security_flags_handle_must_flags(unsigned int *flags) } static ssize_t cifs_security_flags_proc_write(struct file *file, - const char __user *buffer, size_t count, loff_t *ppos) + char *flags_string, size_t count, loff_t *ppos) { int rc; unsigned int flags; - char flags_string[12]; bool bv; if ((count < 1) || (count > 11)) return -EINVAL; - memset(flags_string, 0, sizeof(flags_string)); - - if (copy_from_user(flags_string, buffer, count)) - return -EFAULT; - if (count < 3) { /* single char or single char followed by null */ if (kstrtobool(flags_string, &bv) == 0) { @@ -1176,7 +1166,7 @@ static ssize_t cifs_security_flags_proc_write(struct file *file, static const struct proc_ops cifs_security_flags_proc_ops = { .proc_show = cifs_security_flags_proc_show, - .proc_write = cifs_security_flags_proc_write, + .proc_write_buf = cifs_security_flags_proc_write, }; /* To make it easier to debug, can help to show mount params */ diff --git a/fs/smb/client/dfs_cache.c b/fs/smb/client/dfs_cache.c index 58f16cf83d36..a6aa05430b15 100644 --- a/fs/smb/client/dfs_cache.c +++ b/fs/smb/client/dfs_cache.c @@ -191,17 +191,10 @@ static int dfscache_proc_show(struct seq_file *m, void *v) return 0; } -static ssize_t dfscache_proc_write(struct file *file, const char __user *buffer, +static ssize_t dfscache_proc_write(struct file *file, char *buffer, size_t count, loff_t *ppos) { - char c; - int rc; - - rc = get_user(c, buffer); - if (rc) - return rc; - - if (c != '0') + if (buffer[0] != '0') return -EINVAL; cifs_dbg(FYI, "clearing dfs cache\n"); @@ -215,7 +208,7 @@ static ssize_t dfscache_proc_write(struct file *file, const char __user *buffer, const struct proc_ops dfscache_proc_ops = { .proc_show = dfscache_proc_show, - .proc_write = dfscache_proc_write, + .proc_write_buf = dfscache_proc_write, }; #ifdef CONFIG_CIFS_DEBUG2 -- 2.53.0
