hush: fix SEGV in % expansion

function                                             old     new   delta
expand_variables                                    2203    2217     +14

6 files changed, 31 insertions, 31 deletions

diff --git a/shell/hush.c b/shell/hush.c
index fcbd96c4d..2ad8ebacb 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -1990,12 +1990,9 @@ static int expand_vars_to_list(o_string *output, int n, char *arg, char or_mask)
          * (expansion of right-hand side of assignment == 1-element expand.
          * It will also do no globbing, and thus we must not backslash-quote!) */
 
-        char first_ch, ored_ch;
-        int i;
-        const char *val;
-        char *dyn_val, *p;
+        char ored_ch;
+        char *p;
 
-        dyn_val = NULL;
         ored_ch = 0;
 
         debug_printf_expand("expand_vars_to_list: arg '%s'\n", arg);
@@ -2004,6 +2001,10 @@ static int expand_vars_to_list(o_string *output, int n, char *arg, char or_mask)
         debug_print_list("expand_vars_to_list[0]", output, n);
 
         while ((p = strchr(arg, SPECIAL_VAR_SYMBOL)) != NULL) {
+                char first_ch;
+                int i;
+                char *dyn_val = NULL;
+                const char *val = NULL;
 #if ENABLE_HUSH_TICK
                 o_string subst_result = NULL_O_STRING;
 #endif
@@ -2021,7 +2022,6 @@ static int expand_vars_to_list(o_string *output, int n, char *arg, char or_mask)
                 if ((first_ch & 0x7f) != '@')
                         ored_ch |= first_ch;
 
-                val = NULL;
                 switch (first_ch & 0x7f) {
                 /* Highest bit in first_ch indicates that var is double-quoted */
                 case '$': /* pid */
@@ -2194,16 +2194,16 @@ static int expand_vars_to_list(o_string *output, int n, char *arg, char or_mask)
                                 if (exp_op == '%' || exp_op == '#') {
                                         if (val) {
                                                 /* we need to do a pattern match */
-                                                bool zero;
+                                                bool match_at_left;
                                                 char *loc;
-                                                scan_t scan = pick_scan(exp_op, *exp_word, &zero);
+                                                scan_t scan = pick_scan(exp_op, *exp_word, &match_at_left);
                                                 if (exp_op == *exp_word)        /* ## or %% */
                                                         ++exp_word;
                                                 val = dyn_val = xstrdup(val);
-                                                loc = scan(dyn_val, exp_word, zero);
-                                                if (zero)
+                                                loc = scan(dyn_val, exp_word, match_at_left);
+                                                if (match_at_left) /* # or ## */
                                                         val = loc;
-                                                else
+                                                else if (loc) /* % or %% and match was found */
                                                         *loc = '\0';
                                         }
                                 } else {
@@ -2263,11 +2263,11 @@ static int expand_vars_to_list(o_string *output, int n, char *arg, char or_mask)
                         }
                 } /* default: */
                 } /* switch (char after <SPECIAL_VAR_SYMBOL>) */
+
                 if (val) {
                         o_addQstr(output, val, strlen(val));
                 }
                 free(dyn_val);
-                dyn_val = NULL;
                 /* Do the check to avoid writing to a const string */
                 if (*p != SPECIAL_VAR_SYMBOL)
                         *p = SPECIAL_VAR_SYMBOL;
diff --git a/shell/hush_test/hush-arith/arith.right b/shell/hush_test/hush-arith/arith.right
index 8cde0ee53..83155fb03 100644
--- a/shell/hush_test/hush-arith/arith.right
+++ b/shell/hush_test/hush-arith/arith.right
@@ -63,9 +63,9 @@ hush: error in arithmetic
 40 40
 hush: error in arithmetic
 hush: divide by 0
-hush: can't exec 'let': No such file or directory
+hush: can't execute 'let': No such file or directory
 hush: error in arithmetic
-hush: can't exec 'let': No such file or directory
+hush: can't execute 'let': No such file or directory
 abc
 def
 ghi
@@ -135,4 +135,4 @@ hush: error in arithmetic
 42
 42
 42
-hush: can't exec 'a[b[c]d]=e': No such file or directory
+hush: can't execute 'a[b[c]d]=e': No such file or directory
diff --git a/shell/hush_test/hush-vars/var_posix1.right b/shell/hush_test/hush-vars/var_posix1.right
index 47d52a6c2..e6cba2758 100644
--- a/shell/hush_test/hush-vars/var_posix1.right
+++ b/shell/hush_test/hush-vars/var_posix1.right
@@ -32,4 +32,5 @@ ababcdc
 ababcdcd
 Empty:
 ababcdcd}_tail
+ababcdcd
 end
diff --git a/shell/hush_test/hush-vars/var_posix1.tests b/shell/hush_test/hush-vars/var_posix1.tests
index 3069360e1..c1f64094d 100755
--- a/shell/hush_test/hush-vars/var_posix1.tests
+++ b/shell/hush_test/hush-vars/var_posix1.tests
@@ -43,5 +43,6 @@ echo ${var%*}
 echo Empty:${var%%*}
 echo ${var#}}_tail
 # UNFIXED BUG: echo ${var#\}}_tail
+echo ${var%\\*}
 
 echo end
diff --git a/shell/match.c b/shell/match.c
index 47038d667..a7101ef7e 100644
--- a/shell/match.c
+++ b/shell/match.c
@@ -11,8 +11,6 @@
  * Kenneth Almquist.
  *
  * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
- *
- * Original BSD copyright notice is retained at the end of this file.
  */
 #ifdef STANDALONE
 # include <stdbool.h>
@@ -28,7 +26,7 @@
 
 #define pmatch(a, b) !fnmatch((a), (b), 0)
 
-char *scanleft(char *string, char *pattern, bool zero)
+char *scanleft(char *string, char *pattern, bool match_at_left)
 {
         char c;
         char *loc = string;
@@ -38,7 +36,7 @@ char *scanleft(char *string, char *pattern, bool zero)
                 const char *s;
 
                 c = *loc;
-                if (zero) {
+                if (match_at_left) {
                         *loc = '\0';
                         s = string;
                 } else
@@ -55,7 +53,7 @@ char *scanleft(char *string, char *pattern, bool zero)
         return NULL;
 }
 
-char *scanright(char *string, char *pattern, bool zero)
+char *scanright(char *string, char *pattern, bool match_at_left)
 {
         char c;
         char *loc = string + strlen(string);
@@ -65,7 +63,7 @@ char *scanright(char *string, char *pattern, bool zero)
                 const char *s;
 
                 c = *loc;
-                if (zero) {
+                if (match_at_left) {
                         *loc = '\0';
                         s = string;
                 } else
@@ -88,7 +86,7 @@ int main(int argc, char *argv[])
         char *string;
         char *op;
         char *pattern;
-        bool zero;
+        bool match_at_left;
         char *loc;
 
         int i;
@@ -117,15 +115,15 @@ int main(int argc, char *argv[])
                         continue;
                 }
                 op = string + off;
-                scan = pick_scan(op[0], op[1], &zero);
+                scan = pick_scan(op[0], op[1], &match_at_left);
                 pattern = op + 1;
                 if (op[0] == op[1])
                         op[1] = '\0', ++pattern;
                 op[0] = '\0';
 
-                loc = scan(string, pattern, zero);
+                loc = scan(string, pattern, match_at_left);
 
-                if (zero) {
+                if (match_at_left) {
                         printf("'%s'\n", loc);
                 } else {
                         *loc = '\0';
diff --git a/shell/match.h b/shell/match.h
index 3fc4de340..90597ee54 100644
--- a/shell/match.h
+++ b/shell/match.h
@@ -2,12 +2,12 @@
 
 PUSH_AND_SET_FUNCTION_VISIBILITY_TO_HIDDEN
 
-typedef char *(*scan_t)(char *string, char *match, bool zero);
+typedef char *(*scan_t)(char *string, char *match, bool match_at_left);
 
-char *scanleft(char *string, char *match, bool zero);
-char *scanright(char *string, char *match, bool zero);
+char *scanleft(char *string, char *match, bool match_at_left);
+char *scanright(char *string, char *match, bool match_at_left);
 
-static inline scan_t pick_scan(char op1, char op2, bool *zero)
+static inline scan_t pick_scan(char op1, char op2, bool *match_at_left)
 {
         /* #  - scanleft
          * ## - scanright
@@ -15,10 +15,10 @@ static inline scan_t pick_scan(char op1, char op2, bool *zero)
          * %% - scanleft
          */
         if (op1 == '#') {
-                *zero = true;
+                *match_at_left = true;
                 return op1 == op2 ? scanright : scanleft;
         } else {
-                *zero = false;
+                *match_at_left = false;
                 return op1 == op2 ? scanleft : scanright;
         }
 }