depmod: ignore related modules in depmod_report_cycles

Only print actual cyclic dependencies. Print count of all the modules
in cyclic dependency at the end of the function so that dependent
modules which are not in cyclic chain can be ignored.

Printing dependent modules which are not in cyclic chain causes buffer
overflow as m->modnamesz is not included in buffer size calculations
(loop == m is never true). This buffer overflow causes kmod to crash.

Update depmod test to reflect the change as well.

Reported-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Mian Yousaf Kaukab <yousaf.kaukab@suse.com>

diff --git a/testsuite/rootfs-pristine/test-depmod/detect-loop/correct.txt b/testsuite/rootfs-pristine/test-depmod/detect-loop/correct.txt
index 4eb26dffb7d955d3c3e031dbffba2bec0ca8883e..01ecb894578078dfc1a07e610855bb95aad2cc22 100644 (file)
--- a/testsuite/rootfs-pristine/test-depmod/detect-loop/correct.txt
+++ b/testsuite/rootfs-pristine/test-depmod/detect-loop/correct.txt
@@ -1,3 +1,3 @@
-depmod: ERROR: Found 5 modules in dependency cycles!
 depmod: ERROR: Cycle detected: mod_loop_d -> mod_loop_e -> mod_loop_d
 depmod: ERROR: Cycle detected: mod_loop_b -> mod_loop_c -> mod_loop_a -> mod_loop_b
+depmod: ERROR: Found 5 modules in dependency cycles!

diff --git a/tools/depmod.c b/tools/depmod.c
index ad01f66707b7e8d6deb488ab26afb3ae09696c8a..f2b370f146bba28d31b603e58b18052967f58d72 100644 (file)
--- a/tools/depmod.c
+++ b/tools/depmod.c
@@ -1456,7 +1456,7 @@ static void depmod_report_cycles(struct depmod *depmod, uint16_t n_mods,
 {
        const char sep[] = " -> ";
        int ir = 0;
-       ERR("Found %u modules in dependency cycles!\n", n_roots);
+       int num_cyclic = 0;
 
        while (n_roots > 0) {
                int is, ie;
@@ -1491,6 +1491,7 @@ static void depmod_report_cycles(struct depmod *depmod, uint16_t n_mods,
                        if (m->visited) {
                                int i, n = 0, sz = 0;
                                char *buf;
+                               bool is_cyclic = false;
 
                                for (i = ie - 1; i >= 0; i--) {
                                        struct mod *loop = depmod->modules.array[edges[i]];
@@ -1498,9 +1499,17 @@ static void depmod_report_cycles(struct depmod *depmod, uint16_t n_mods,
                                        n++;
                                        if (loop == m) {
                                                sz += loop->modnamesz - 1;
+                                               is_cyclic = true;
                                                break;
                                        }
                                }
+                               /* Current module not found in dependency list.
+                                * Must be a related module. Ignore it.
+                                */
+                               if (!is_cyclic)
+                                       continue;
+
+                               num_cyclic += n;
 
                                buf = malloc(sz + n * strlen(sep) + 1);
                                sz = 0;
@@ -1538,6 +1547,8 @@ static void depmod_report_cycles(struct depmod *depmod, uint16_t n_mods,
                        }
                }
        }
+
+       ERR("Found %d modules in dependency cycles!\n", num_cyclic);
 }
 
 static int depmod_calculate_dependencies(struct depmod *depmod)