--- /dev/null
+From: Goswin Brederlow <goswin.brederlow@student.uni-tuebingen.de>
+Subject: Bug#129345: patch to prevent a loop between libdl and libsafe causing libdl to crash
+To: 129345@bugs.debian.org
+Date: 01 Sep 2002 23:54:35 +0200
+Reply-To: Goswin Brederlow <goswin.brederlow@student.uni-tuebingen.de>,
+ 129345@bugs.debian.org
+Resent-From: Goswin Brederlow <goswin.brederlow@student.uni-tuebingen.de>
+
+
+-------
+[D. Coe edited this patch slightly -- moved an unrelated change into the
+Makefile itself [it changed the debugging comments only], and corrected a
+spelling error and reworded the comments. The original patch is in the
+bug tracking system, if you want to see it as submitted by Goswin.]
+-------
+-------
+D. Coe subsequently modified the patch further, because in some cases
+the initializations did not occur (e.g. when IO_vfscanf or memcpy was
+called from ps or top (likely one of the libraries they use). maybe
+they do something that disables libsafe's library globals initialization?
+
+
+In any case, I've adopted both strategise in this new patch; the addresses
+are preloaded as Goswin had coded, but they are also individually checked
+each time needed (as was the case before Goswin's patch), and are initialized
+at that point if necessary. Hopefully this will let ps and top work
+and also continue to work around the libdl problem.
+-------
+
+Hi,
+
+if libsafe is invoked from inside libdl (or only inside dlerror()?)
+and a real_XXX function is not yet looked up it will reenter
+libdl. That causes memory corruption resulting in a read from 0x0 and
+thus segfault.
+
+The patch below makes libsafe cache all needed symbols once upon
+init. That not only causes less lookups than before but should prevent
+fatal loops. Failures of the initial lookups might not be reported
+correctly but terminate in some odd way if the functions needed to
+report are not yet looked up.
+
+MfG
+ Goswin
+
+----------------------------------------------------------------------
+diff -Nurd libsafe-2.0-16/src/intercept.c libsafe-2.0-16-mrvn/src/intercept.c
+--- libsafe-2.0-16/src/intercept.c 2002-05-31 19:37:34.000000000 +0200
++++ libsafe-2.0-16-mrvn/src/intercept.c 2002-09-01 23:44:55.000000000 +0200
+@@ -128,14 +128,29 @@
+ }
+
+
+-/* Starting with version 2.0, we keep a single global copy of the pointer to
+- * the real memcpy() function. This allows us to call
+- * getLibraryFunction("memcpy") just once instead of multiple times, since
+- * memcpy() is needed in four different functions below.
++/* Starting with Debian version 2.0-16-2, we keep a global copy of the pointer
++ * to each real functions. Otherwise a getLibraryFunction might
++ * be triggered from inside dlsym() and cause memory corruption reulting in a
++ * segfault.
+ */
+-static memcpy_t real_memcpy = NULL;
+-
+-
++static memcpy_t real_memcpy = NULL;
++static _IO_vfscanf_t real_IO_vfscanf = NULL;
++static vfprintf_t real_vfprintf = NULL;
++static vsnprintf_t real_vsnprintf = NULL;
++static vsprintf_t real_vsprintf = NULL;
++static gets_t real_gets = NULL;
++static getwd_t real_getwd = NULL;
++static realpath_t real_realpath = NULL;
++static stpcpy_t real_stpcpy = NULL;
++static strcat_t real_strcat = NULL;
++static strcpy_t real_strcpy = NULL;
++static strncat_t real_strncat = NULL;
++static strncpy_t real_strncpy = NULL;
++static wcscpy_t real_wcscpy = NULL;
++static wcpcpy_t real_wcpcpy = NULL;
++#ifndef MISSING_WCSNLEN
++static wcscat_t real_wcscat = NULL;
++#endif
+ /*
+ * -------------- system library implementations -------------------
+ * Here is the story: if a C source file includes <string.h> and is
+@@ -150,7 +165,6 @@
+ */
+ char *strcpy(char *dest, const char *src)
+ {
+- static strcpy_t real_strcpy = NULL;
+ size_t max_size, len;
+
+ if (!real_memcpy)
+@@ -182,7 +196,6 @@
+
+ char *strncpy(char *dest, const char *src, size_t n)
+ {
+- static strncpy_t real_strncpy = NULL;
+ size_t max_size, len;
+
+ if (!real_strncpy)
+@@ -206,7 +219,6 @@
+
+ char *stpcpy(char *dest, const char *src)
+ {
+- static stpcpy_t real_stpcpy = NULL;
+ size_t max_size, len;
+
+ if (!real_memcpy)
+@@ -239,7 +251,6 @@
+ #ifndef MISSING_WCSNLEN
+ wchar_t *wcscpy(wchar_t *dest, const wchar_t *src)
+ {
+- static wcscpy_t real_wcscpy = NULL;
+ size_t max_bytes, max_wchars, len;
+
+ if (!real_wcscpy)
+@@ -280,7 +291,6 @@
+
+ wchar_t *wcpcpy(wchar_t *dest, const wchar_t *src)
+ {
+- static wcpcpy_t real_wcpcpy = NULL;
+ size_t max_bytes, max_wchars, len;
+
+ if (!real_wcpcpy)
+@@ -347,7 +357,6 @@
+
+ char *strcat(char *dest, const char *src)
+ {
+- static strcat_t real_strcat = NULL;
+ size_t max_size;
+ uint dest_len, src_len;
+
+@@ -379,7 +388,6 @@
+
+ char *strncat(char *dest, const char *src, size_t n)
+ {
+- static strncat_t real_strncat = NULL;
+ size_t max_size;
+ uint dest_len, src_len;
+
+@@ -408,7 +416,6 @@
+ #ifndef MISSING_WCSNLEN
+ wchar_t *wcscat(wchar_t *dest, const wchar_t *src)
+ {
+- static wcscat_t real_wcscat = NULL;
+ size_t max_bytes;
+ uint dest_len, src_len;
+
+@@ -861,7 +868,6 @@
+ */
+ int vfprintf(FILE *fp, const char *format, va_list ap)
+ {
+- static vfprintf_t real_vfprintf = NULL;
+ int res;
+ char *p, *pnum;
+ int c = -1; /* Next var arg to be used */
+@@ -1026,7 +1032,6 @@
+ */
+ int _IO_vfprintf(FILE *fp, const char *format, va_list ap)
+ {
+- static vfprintf_t real_vfprintf = NULL;
+ int res;
+ char *p, *pnum;
+ int c = -1; /* Next var arg to be used */
+@@ -1189,8 +1194,6 @@
+
+ int sprintf(char *str, const char *format, ...)
+ {
+- static vsprintf_t real_vsprintf = NULL;
+- static vsnprintf_t real_vsnprintf = NULL;
+ size_t max_size;
+ va_list ap;
+ int res;
+@@ -1239,7 +1242,6 @@
+
+ int snprintf(char *str, size_t size, const char *format, ...)
+ {
+- static vsnprintf_t real_vsnprintf = NULL;
+ size_t max_size;
+ va_list ap;
+ int res;
+@@ -1286,8 +1288,6 @@
+
+ int vsprintf(char *str, const char *format, va_list ap)
+ {
+- static vsprintf_t real_vsprintf = NULL;
+- static vsnprintf_t real_vsnprintf = NULL;
+ size_t max_size;
+ int res;
+
+@@ -1325,7 +1325,6 @@
+
+ int vsnprintf(char *str, size_t size, const char *format, va_list ap)
+ {
+- static vsnprintf_t real_vsnprintf = NULL;
+ size_t max_size;
+ int res;
+
+@@ -1361,7 +1360,6 @@
+
+ char *getwd(char *buf)
+ {
+- static getwd_t real_getwd = NULL;
+ size_t max_size;
+ char *res;
+
+@@ -1386,7 +1384,6 @@
+
+ char *gets(char *s)
+ {
+- static gets_t real_gets = NULL;
+ size_t max_size, len;
+
+ if (!real_gets)
+@@ -1412,7 +1409,6 @@
+
+ char *realpath(char *path, char resolved_path[])
+ {
+- static realpath_t real_realpath = NULL;
+ size_t max_size, len;
+ char *res;
+ char buf[MAXPATHLEN + 1];
+@@ -1445,7 +1441,6 @@
+
+ int _IO_vfscanf (_IO_FILE *s, const char *format, _IO_va_list argptr, int *errp)
+ {
+- static _IO_vfscanf_t real_IO_vfscanf = NULL;
+ int res, save_count;
+ caddr_t ra_array[MAXLEVELS], fp_array[MAXLEVELS];
+
+@@ -1529,6 +1524,25 @@
+
+ fclose(fp);
+ }
++
++ real_memcpy = (memcpy_t) getLibraryFunction("memcpy");
++ real_IO_vfscanf = (_IO_vfscanf_t) getLibraryFunction("_IO_vfscanf");
++ real_vfprintf = (vfprintf_t) getLibraryFunction("vfprintf");
++ real_vsnprintf = (vsnprintf_t) getLibraryFunction("vsnprintf");
++ real_vsprintf = (vsprintf_t) getLibraryFunction("vsprintf");
++ real_gets = (gets_t) getLibraryFunction("gets");
++ real_getwd = (getwd_t) getLibraryFunction("getwd");
++ real_realpath = (realpath_t) getLibraryFunction("realpath");
++ real_stpcpy = (stpcpy_t) getLibraryFunction("stpcpy");
++ real_strcat = (strcat_t) getLibraryFunction("strcat");
++ real_strcpy = (strcpy_t) getLibraryFunction("strcpy");
++ real_strncat = (strncat_t) getLibraryFunction("strncat");
++ real_strncpy = (strncpy_t) getLibraryFunction("strncpy");
++ real_wcscpy = (wcscpy_t) getLibraryFunction("wcscpy");
++ real_wcpcpy = (wcpcpy_t) getLibraryFunction("wcpcpy");
++#ifndef MISSING_WCSNLEN
++ real_wcscat = (wcscat_t) getLibraryFunction("wcscat");
++#endif
+ }
+
+
projects / people / teissler / ipfire-2.x.git / blobdiff