From cb008bcace2510f157ccec2df4e5ff254513b7c4 Mon Sep 17 00:00:00 2001

From: Ludwig Krispenz <lkrispen@redhat.com>

Date: Mon, 15 Jan 2018 10:24:41 +0100

Subject: [PATCH] CVE 2017-15134 - crash in slapi_filter_sprintf

Signed-off-by: Mark Reynolds <mreynolds@redhat.com>

---

 ldap/servers/slapd/util.c | 36 +++++++++++++++++++++++++++++++-----

 1 file changed, 31 insertions(+), 5 deletions(-)

diff --git a/ldap/servers/slapd/util.c b/ldap/servers/slapd/util.c

index a72de9b07..ddb2cc899 100644

--- a/ldap/servers/slapd/util.c

+++ b/ldap/servers/slapd/util.c

@@ -238,9 +238,10 @@ escape_string_for_filename(const char *str, char buf[BUFSIZ])

 struct filter_ctx

 {

     char *buf;

-    char attr[ATTRSIZE];

+    char *attr;

     int attr_position;

     int attr_found;

+    size_t attr_size;

     int buf_size;

     int buf_len;

     int next_arg_needs_esc_norm;

@@ -279,7 +280,7 @@ filter_stuff_func(void *arg, const char *val, PRUint32 slen)

      *  Start collecting the attribute name so we can use the correct

      *  syntax normalization func.

      */

-    if (ctx->attr_found == 0 && ctx->attr_position < (ATTRSIZE - 1)) {

+    if (ctx->attr_found == 0 && ctx->attr_position < (ctx->attr_size - 1)) {

         if (ctx->attr[0] == '\0') {

             if (strstr(val, "=")) {

                 /* we have an attr we need to record */

@@ -293,6 +294,14 @@ filter_stuff_func(void *arg, const char *val, PRUint32 slen)

                  *  attr with val.  The next pass should be '=', otherwise we will

                  *  reset it.

                  */

+                if (slen > ctx->attr_size) {

+                    if (ctx->attr_size == ATTRSIZE) {

+                        ctx->attr = slapi_ch_calloc(sizeof(char), slen+1);

+                    } else {

+                        ctx->attr = slapi_ch_realloc(ctx->attr, sizeof(char) * (slen+1));

+                    }

+                    ctx->attr_size = slen+1;

+                }

                 memcpy(ctx->attr, val, slen);

                 ctx->attr_position = slen;

             }

@@ -302,9 +311,20 @@ filter_stuff_func(void *arg, const char *val, PRUint32 slen)

             } else {

                 if (special_attr_char(val[0])) {

                     /* this is not an attribute, we should not be collecting this, reset everything */

-                    memset(ctx->attr, '\0', ATTRSIZE);

+                    memset(ctx->attr, '\0', ctx->attr_size);

                     ctx->attr_position = 0;

                 } else {

+                    /* we can be adding char by char and overrun allocated size */

+                    if (ctx->attr_position >= ctx->attr_size) {

+                        if (ctx->attr_size == ATTRSIZE) {

+                            char *ctxattr = slapi_ch_calloc(sizeof(char), ctx->attr_size + ATTRSIZE);

+                            memcpy(ctxattr, ctx->attr, ctx->attr_size);

+                            ctx->attr = ctxattr;

+                        } else {

+                            ctx->attr = slapi_ch_realloc(ctx->attr, sizeof(char) * (ctx->attr_size + ATTRSIZE));

+                        }

+                        ctx->attr_size = ctx->attr_size + ATTRSIZE;

+                    }

                     memcpy(ctx->attr + ctx->attr_position, val, 1);

                     ctx->attr_position++;

                 }

@@ -377,7 +397,7 @@ filter_stuff_func(void *arg, const char *val, PRUint32 slen)

         ctx->next_arg_needs_esc_norm = 0;

         ctx->attr_found = 0;

         ctx->attr_position = 0;

-        memset(ctx->attr, '\0', ATTRSIZE);

+        memset(ctx->attr, '\0', ctx->attr_size);

         slapi_ch_free_string(&buf;;

         return filter_len;

@@ -416,12 +436,14 @@ slapi_filter_sprintf(const char *fmt, ...)

 {

     struct filter_ctx ctx = {0};

     va_list args;

+    char attr_static[ATTRSIZE] = {0};

     char *buf;

     int rc;

     buf = slapi_ch_calloc(sizeof(char), FILTER_BUF + 1);

     ctx.buf = buf;

-    memset(ctx.attr, '\0', ATTRSIZE);

+    ctx.attr = attr_static;

+    ctx.attr_size = ATTRSIZE;

     ctx.attr_position = 0;

     ctx.attr_found = 0;

     ctx.buf_len = FILTER_BUF;

@@ -438,6 +460,10 @@ slapi_filter_sprintf(const char *fmt, ...)

     }

     va_end(args);

+    if (ctx.attr_size > ATTRSIZE) {

+        slapi_ch_free_string(&ctx.attr);

+    }

+

     return ctx.buf;

 }

-- 

2.13.6