[PATCH v4 3/6] Improve fd filtering
Nikolay Marchuk
marchuk.nikolay.a at gmail.com
Fri Jul 14 14:55:32 UTC 2017
* pathtrace.c (match_fd_common, pathtrace_match_set): Move fd matching to
separate function.
* filter.h (match_fd_common): Add new declaration.
* basic_filters.c (run_fd_filter): Use match_fd_common for fd filter.
---
basic_filters.c | 52 +++++++++++++++--
filter.h | 2 +
pathtrace.c | 170 ++++++++++++++++++++++++++++++++------------------------
3 files changed, 146 insertions(+), 78 deletions(-)
diff --git a/basic_filters.c b/basic_filters.c
index d8842b5..577eb02 100644
--- a/basic_filters.c
+++ b/basic_filters.c
@@ -29,6 +29,7 @@
#include "defs.h"
#include <regex.h>
#include "filter.h"
+#include "syscall.h"
typedef unsigned int number_slot_t;
#define BITS_PER_SLOT (sizeof(number_slot_t) * 8)
@@ -407,14 +408,57 @@ parse_fd_filter(const char *str)
return set;
}
+static bool
+is_fd_in_set(struct tcb *tcp, int fd, void *data) {
+ if (fd < 0)
+ return false;
+ struct number_set *set = data;
+ return is_number_in_set(fd, set);
+}
+
bool
run_fd_filter(struct tcb *tcp, void *_priv_data)
{
- int fd = tcp->u_arg[0];
- if (fd < 0)
- return false;
struct number_set *set = _priv_data;
- return is_number_in_set(fd, set);
+ const struct_sysent *s_ent = tcp->s_ent;
+ /*
+ * mq_timedsend and mq_timedreceive are not marked as descriptor
+ * syscalls, but they can be dumped with -e read/write.
+ */
+ switch (s_ent->sen) {
+ case SEN_mq_timedsend:
+ case SEN_mq_timedreceive:
+ return is_fd_in_set(tcp, tcp->u_arg[0], set);
+ }
+
+ if (!(s_ent->sys_flags & (TRACE_DESC | TRACE_NETWORK)))
+ return false;
+
+ if (match_fd_common(tcp, &is_fd_in_set, set))
+ return true;
+
+ switch (s_ent->sen) {
+ case SEN_bpf:
+ case SEN_creat:
+ case SEN_epoll_create:
+ case SEN_epoll_create1:
+ case SEN_eventfd2:
+ case SEN_eventfd:
+ case SEN_fanotify_init:
+ case SEN_inotify_init1:
+ case SEN_memfd_create:
+ case SEN_open:
+ case SEN_perf_event_open:
+ case SEN_pipe:
+ case SEN_pipe2:
+ case SEN_printargs:
+ case SEN_socket:
+ case SEN_socketpair:
+ case SEN_timerfd_create:
+ case SEN_userfaultfd:
+ return false;
+ }
+ return is_fd_in_set(tcp, tcp->u_arg[0], set);
}
void
diff --git a/filter.h b/filter.h
index 7525b15..0017d6c 100644
--- a/filter.h
+++ b/filter.h
@@ -41,6 +41,8 @@ void parse_set(const char *const, struct number_set *const,
string_to_uint_func, const char *const);
void parse_inject_common_args(char *, struct inject_opts *, const char *delim,
const bool fault_tokens_only);
+typedef bool (*match_fd_func)(struct tcb *, int, void *);
+bool match_fd_common(struct tcb *, match_fd_func, void *);
/* filter api */
struct filter* add_filter_to_array(struct filter **, unsigned int *nfilters,
diff --git a/pathtrace.c b/pathtrace.c
index 9f3674a..e9ad7fb 100644
--- a/pathtrace.c
+++ b/pathtrace.c
@@ -143,25 +143,20 @@ pathtrace_select_set(const char *path, struct path_set *set)
storepath(rpath, set);
}
-/*
- * Return true if syscall accesses a selected path
- * (or if no paths have been specified for tracing).
- */
-bool
-pathtrace_match_set(struct tcb *tcp, struct path_set *set)
-{
- const struct_sysent *s;
+typedef bool (*match_fd_func)(struct tcb *, int, void *);
- s = tcp->s_ent;
+static
+bool fdmatch_fd_func(struct tcb *tcp, int fd, void *data)
+{
+ return fdmatch(tcp, fd, (struct path_set *) data);
+}
- if (!(s->sys_flags & (TRACE_FILE | TRACE_DESC | TRACE_NETWORK)))
+bool
+match_fd_common(struct tcb *tcp, match_fd_func func, void *data)
+{
+ const struct_sysent *s = tcp->s_ent;
+ if (!(s->sys_flags & (TRACE_DESC | TRACE_NETWORK)))
return false;
-
- /*
- * Check for special cases where we need to do something
- * other than test arg[0].
- */
-
switch (s->sen) {
case SEN_dup2:
case SEN_dup3:
@@ -170,47 +165,17 @@ pathtrace_match_set(struct tcb *tcp, struct path_set *set)
case SEN_sendfile64:
case SEN_tee:
/* fd, fd */
- return fdmatch(tcp, tcp->u_arg[0], set) ||
- fdmatch(tcp, tcp->u_arg[1], set);
-
- case SEN_faccessat:
- case SEN_fchmodat:
- case SEN_fchownat:
- case SEN_fstatat64:
- case SEN_futimesat:
- case SEN_inotify_add_watch:
- case SEN_mkdirat:
- case SEN_mknodat:
- case SEN_name_to_handle_at:
- case SEN_newfstatat:
- case SEN_openat:
- case SEN_readlinkat:
- case SEN_statx:
- case SEN_unlinkat:
- case SEN_utimensat:
- /* fd, path */
- return fdmatch(tcp, tcp->u_arg[0], set) ||
- upathmatch(tcp, tcp->u_arg[1], set);
-
- case SEN_link:
- case SEN_mount:
- case SEN_pivotroot:
- /* path, path */
- return upathmatch(tcp, tcp->u_arg[0], set) ||
- upathmatch(tcp, tcp->u_arg[1], set);
-
- case SEN_quotactl:
- /* x, path */
- return upathmatch(tcp, tcp->u_arg[1], set);
+ return func(tcp, tcp->u_arg[0], data) ||
+ func(tcp, tcp->u_arg[1], data);
case SEN_linkat:
case SEN_renameat2:
case SEN_renameat:
- /* fd, path, fd, path */
- return fdmatch(tcp, tcp->u_arg[0], set) ||
- fdmatch(tcp, tcp->u_arg[2], set) ||
- upathmatch(tcp, tcp->u_arg[1], set) ||
- upathmatch(tcp, tcp->u_arg[3], set);
+ case SEN_copy_file_range:
+ case SEN_splice:
+ /* fd, x, fd */
+ return func(tcp, tcp->u_arg[0], data) ||
+ func(tcp, tcp->u_arg[2], data);
case SEN_old_mmap:
#if defined(S390)
@@ -221,30 +186,17 @@ pathtrace_match_set(struct tcb *tcp, struct path_set *set)
case SEN_mmap_pgoff:
case SEN_ARCH_mmap:
/* x, x, x, x, fd */
- return fdmatch(tcp, tcp->u_arg[4], set);
-
+ return func(tcp, tcp->u_arg[4], data);
case SEN_symlinkat:
- /* path, fd, path */
- return fdmatch(tcp, tcp->u_arg[1], set) ||
- upathmatch(tcp, tcp->u_arg[0], set) ||
- upathmatch(tcp, tcp->u_arg[2], set);
-
- case SEN_copy_file_range:
- case SEN_splice:
- /* fd, x, fd, x, x, x */
- return fdmatch(tcp, tcp->u_arg[0], set) ||
- fdmatch(tcp, tcp->u_arg[2], set);
-
+ /* x, fd, x */
+ return func(tcp, tcp->u_arg[1], data);
case SEN_epoll_ctl:
/* x, x, fd, x */
- return fdmatch(tcp, tcp->u_arg[2], set);
-
+ return func(tcp, tcp->u_arg[2], data);
case SEN_fanotify_mark:
- /* x, x, x, fd, path */
- return fdmatch(tcp, tcp->u_arg[3], set) ||
- upathmatch(tcp, tcp->u_arg[4], set);
-
+ /* x, x, x, fd, x */
+ return func(tcp, tcp->u_arg[3], data);
case SEN_oldselect:
case SEN_pselect6:
case SEN_select:
@@ -299,7 +251,7 @@ pathtrace_match_set(struct tcb *tcp, struct path_set *set)
j = next_set_bit(fds, j, nfds);
if (j < 0)
break;
- if (fdmatch(tcp, j, set)) {
+ if (func(tcp, j, data)) {
free(fds);
return true;
}
@@ -326,11 +278,81 @@ pathtrace_match_set(struct tcb *tcp, struct path_set *set)
for (cur = start; cur < end; cur += sizeof(fds))
if ((umove(tcp, cur, &fds) == 0)
- && fdmatch(tcp, fds.fd, set))
+ && func(tcp, fds.fd, data))
return true;
return false;
}
+ }
+ return false;
+}
+
+/*
+ * Return true if syscall accesses a selected path
+ * (or if no paths have been specified for tracing).
+ */
+bool
+pathtrace_match_set(struct tcb *tcp, struct path_set *set)
+{
+ const struct_sysent *s;
+
+ s = tcp->s_ent;
+
+ if (!(s->sys_flags & (TRACE_FILE | TRACE_DESC | TRACE_NETWORK)))
+ return false;
+
+ if (match_fd_common(tcp, fdmatch_fd_func, set))
+ return true;
+ /*
+ * Check for special cases where we need to do something
+ * other than test arg[0].
+ */
+
+ switch (s->sen) {
+ case SEN_faccessat:
+ case SEN_fchmodat:
+ case SEN_fchownat:
+ case SEN_fstatat64:
+ case SEN_futimesat:
+ case SEN_inotify_add_watch:
+ case SEN_mkdirat:
+ case SEN_mknodat:
+ case SEN_name_to_handle_at:
+ case SEN_newfstatat:
+ case SEN_openat:
+ case SEN_readlinkat:
+ case SEN_statx:
+ case SEN_unlinkat:
+ case SEN_utimensat:
+ /* x, path */
+ return upathmatch(tcp, tcp->u_arg[1], set);
+
+ case SEN_link:
+ case SEN_mount:
+ case SEN_pivotroot:
+ /* path, path */
+ return upathmatch(tcp, tcp->u_arg[0], set) ||
+ upathmatch(tcp, tcp->u_arg[1], set);
+
+ case SEN_quotactl:
+ /* x, path */
+ return upathmatch(tcp, tcp->u_arg[1], set);
+
+ case SEN_linkat:
+ case SEN_renameat2:
+ case SEN_renameat:
+ /* x, path, x, path */
+ return upathmatch(tcp, tcp->u_arg[1], set) ||
+ upathmatch(tcp, tcp->u_arg[3], set);
+
+ case SEN_symlinkat:
+ /* path, x, path */
+ return upathmatch(tcp, tcp->u_arg[0], set) ||
+ upathmatch(tcp, tcp->u_arg[2], set);
+
+ case SEN_fanotify_mark:
+ /* x, x, x, x, path */
+ return upathmatch(tcp, tcp->u_arg[4], set);
case SEN_bpf:
case SEN_epoll_create:
--
2.1.4
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