From 83c7d09173fdb6b06b109e65895392db3e49ac9c Mon Sep 17 00:00:00 2001 From: Date: Fri, 29 Apr 2005 15:54:44 +0100 Subject: AUDIT: Avoid log pollution by untrusted strings. We log strings from userspace, such as arguments to open(). These could be formatted to contain \n followed by fake audit log entries. Provide a function for logging such strings, which gives a hex dump when the string contains anything but basic printable ASCII characters. Use it for logging filenames. Signed-off-by: David Woodhouse --- include/linux/audit.h | 8 +++++++- kernel/audit.c | 23 +++++++++++++++++++++++ kernel/auditsc.c | 7 ++++--- 3 files changed, 34 insertions(+), 4 deletions(-) diff --git a/include/linux/audit.h b/include/linux/audit.h index 3628f7cfb178..9b77992c4888 100644 --- a/include/linux/audit.h +++ b/include/linux/audit.h @@ -174,11 +174,15 @@ extern void audit_log_format(struct audit_buffer *ab, const char *fmt, ...) __attribute__((format(printf,2,3))); extern void audit_log_end(struct audit_buffer *ab); +extern void audit_log_hex(struct audit_buffer *ab, + const unsigned char *buf, + size_t len); +extern void audit_log_untrustedstring(struct audit_buffer *ab, + const char *string); extern void audit_log_d_path(struct audit_buffer *ab, const char *prefix, struct dentry *dentry, struct vfsmount *vfsmnt); - /* Private API (for auditsc.c only) */ extern void audit_send_reply(int pid, int seq, int type, int done, int multi, @@ -190,6 +194,8 @@ extern void audit_log_lost(const char *message); #define audit_log_vformat(b,f,a) do { ; } while (0) #define audit_log_format(b,f,...) do { ; } while (0) #define audit_log_end(b) do { ; } while (0) +#define audit_log_hex(a,b,l) do { ; } while (0) +#define audit_log_untrustedstring(a,s) do { ; } while (0) #define audit_log_d_path(b,p,d,v) do { ; } while (0) #endif #endif diff --git a/kernel/audit.c b/kernel/audit.c index 0f84dd7af2c8..dca7b99615d2 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -720,6 +720,29 @@ void audit_log_format(struct audit_buffer *ab, const char *fmt, ...) va_end(args); } +void audit_log_hex(struct audit_buffer *ab, const unsigned char *buf, size_t len) +{ + int i; + + for (i=0; i 0x7f) { + audit_log_hex(ab, string, strlen(string)); + return; + } + p++; + } + audit_log_format(ab, "\"%s\"", string); +} + + /* This is a helper-function to print the d_path without using a static * buffer or allocating another buffer in addition to the one in * audit_buffer. */ diff --git a/kernel/auditsc.c b/kernel/auditsc.c index 6f1931381bc9..00e87ffff13b 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -696,9 +696,10 @@ static void audit_log_exit(struct audit_context *context) if (!ab) continue; /* audit_panic has been called */ audit_log_format(ab, "item=%d", i); - if (context->names[i].name) - audit_log_format(ab, " name=%s", - context->names[i].name); + if (context->names[i].name) { + audit_log_format(ab, " name="); + audit_log_untrustedstring(ab, context->names[i].name); + } if (context->names[i].ino != (unsigned long)-1) audit_log_format(ab, " inode=%lu dev=%02x:%02x mode=%#o" " uid=%d gid=%d rdev=%02x:%02x", -- cgit v1.2.1