From d65ea39ffc7503807fa95e8840c012a80c83e4f3 Mon Sep 17 00:00:00 2001 From: Denis Vlasenko Date: Mon, 1 Oct 2007 10:02:25 +0000 Subject: [PATCH] hush: fix glob() abuse. Code was making unfounded assumptions how glob() works, and it broke horribly on specific uclibc config. --- shell/hush.c | 189 ++++++++++++++++++++++++++++++++------------------- 1 file changed, 120 insertions(+), 69 deletions(-) diff --git a/shell/hush.c b/shell/hush.c index e73432a89..90ed15547 100644 --- a/shell/hush.c +++ b/shell/hush.c @@ -246,7 +246,7 @@ struct redir_struct { redir_type type; /* type of redirection */ int fd; /* file descriptor being redirected */ int dup; /* -1, or file descriptor being duplicated */ - glob_t glob_word; /* *word.gl_pathv is the filename */ + char **glob_word; /* *word.gl_pathv is the filename */ }; struct child_prog { @@ -256,7 +256,7 @@ struct child_prog { smallint subshell; /* flag, non-zero if group must be forked */ smallint is_stopped; /* is the program currently running? */ struct redir_struct *redirects; /* I/O redirections */ - glob_t glob_result; /* result of parameter globbing */ + char **glob_result; /* result of parameter globbing */ struct pipe *family; /* pointer back to the child's parent pipe */ //sp counting seems to be broken... so commented out, grep for '//sp:' //sp: int sp; /* number of SPECIAL_VAR_SYMBOL */ @@ -503,9 +503,9 @@ static void pseudo_exec_argv(char **argv) ATTRIBUTE_NORETURN; static void pseudo_exec(struct child_prog *child) ATTRIBUTE_NORETURN; static int run_pipe_real(struct pipe *pi); /* extended glob support: */ -static int globhack(const char *src, int flags, glob_t *pglob); +static char **globhack(const char *src, char **strings); static int glob_needed(const char *s); -static int xglob(o_string *dest, int flags, glob_t *pglob); +static int xglob(o_string *dest, char ***pglob); /* variable assignment: */ static int is_assignment(const char *s); /* data structure manipulation: */ @@ -548,6 +548,58 @@ static struct variable *get_local_var(const char *name); static int set_local_var(char *str, int flg_export); static void unset_local_var(const char *name); + +static char **add_strings_to_strings(int need_xstrdup, char **strings, char **add) +{ + int i; + unsigned count1; + unsigned count2; + char **v; + + v = strings; + count1 = 0; + if (v) { + while (*v) { + count1++; + v++; + } + } + count2 = 0; + v = add; + while (*v) { + count2++; + v++; + } + v = xrealloc(strings, (count1 + count2 + 1) * sizeof(char*)); + v[count1 + count2] = NULL; + i = count2; + while (--i >= 0) + v[count1 + i] = need_xstrdup ? xstrdup(add[i]) : add[i]; + return v; +} + +/* 'add' should be a malloced pointer */ +static char **add_string_to_strings(char **strings, char *add) +{ + char *v[2]; + + v[0] = add; + v[1] = NULL; + + return add_strings_to_strings(0, strings, v); +} + +static void free_strings(char **strings) +{ + if (strings) { + char **v = strings; + while (*v) + free(*v++); + free(strings); + } +} + + /* Table of built-in functions. They can be forked or not, depending on * context: within pipes, they fork. As simple commands, they do not. * When used in non-forking context, they can change global variables @@ -1067,16 +1119,14 @@ static void b_reset(o_string *o) { o->length = 0; o->nonnull = 0; - if (o->data != NULL) - *o->data = '\0'; + if (o->data) + o->data[0] = '\0'; } static void b_free(o_string *o) { - b_reset(o); free(o->data); - o->data = NULL; - o->maxlen = 0; + memset(o, 0, sizeof(*o)); } /* My analysis of quoting semantics tells me that state information @@ -1256,13 +1306,13 @@ static int setup_redirects(struct child_prog *prog, int squirrel[]) struct redir_struct *redir; for (redir = prog->redirects; redir; redir = redir->next) { - if (redir->dup == -1 && redir->glob_word.gl_pathv == NULL) { + if (redir->dup == -1 && redir->glob_word == NULL) { /* something went wrong in the parse. Pretend it didn't happen */ continue; } if (redir->dup == -1) { mode = redir_table[redir->type].mode; - openfd = open_or_warn(redir->glob_word.gl_pathv[0], mode); + openfd = open_or_warn(redir->glob_word[0], mode); if (openfd < 0) { /* this could get lost if stderr has been redirected, but bash and ash both lose it as well (though zsh doesn't!) */ @@ -2024,6 +2074,7 @@ static int run_list_real(struct pipe *pi) #if ENABLE_HUSH_LOOPS if (rword == RES_FOR && pi->num_progs) { if (!for_lcur) { + /* first loop through for */ /* if no variable values after "in" we skip "for" */ if (!pi->next->progs->argv) continue; @@ -2036,17 +2087,16 @@ static int run_list_real(struct pipe *pi) } free(pi->progs->argv[0]); if (!*for_lcur) { + /* for loop is over, clean up */ free(for_list); for_lcur = NULL; flag_rep = 0; pi->progs->argv[0] = for_varname; - pi->progs->glob_result.gl_pathv[0] = pi->progs->argv[0]; continue; } /* insert next value from for_lcur */ /* vda: does it need escaping? */ pi->progs->argv[0] = xasprintf("%s=%s", for_varname, *for_lcur++); - pi->progs->glob_result.gl_pathv[0] = pi->progs->argv[0]; } if (rword == RES_IN) continue; @@ -2149,8 +2199,8 @@ static int free_pipe(struct pipe *pi, int indent) for (a = 0, p = child->argv; *p; a++, p++) { debug_printf_clean("%s argv[%d] = %s\n", indenter(indent), a, *p); } - globfree(&child->glob_result); - child->argv = NULL; + free_strings(child->glob_result); + child->glob_result = NULL; } else if (child->group) { debug_printf_clean("%s begin group (subshell:%d)\n", indenter(indent), child->subshell); ret_code = free_pipe_list(child->group, indent+3); @@ -2162,9 +2212,10 @@ static int free_pipe(struct pipe *pi, int indent) debug_printf_clean("%s redirect %d%s", indenter(indent), r->fd, redir_table[r->type].descrip); if (r->dup == -1) { /* guard against the case >$FOO, where foo is unset or blank */ - if (r->glob_word.gl_pathv) { - debug_printf_clean(" %s\n", r->glob_word.gl_pathv[0]); - globfree(&r->glob_word); + if (r->glob_word) { + debug_printf_clean(" %s\n", r->glob_word[0]); + free_strings(r->glob_word); + r->glob_word = NULL; } } else { debug_printf_clean("&%d\n", r->dup); @@ -2224,80 +2275,79 @@ static int run_list(struct pipe *pi) * string into the output structure, removing non-backslashed backslashes. * If someone can prove me wrong, by performing this function within the * original glob(3) api, feel free to rewrite this routine into oblivion. - * Return code (0 vs. GLOB_NOSPACE) matches glob(3). * XXX broken if the last character is '\\', check that before calling. */ -static int globhack(const char *src, int flags, glob_t *pglob) +static char **globhack(const char *src, char **strings) { - int cnt = 0, pathc; + int cnt; const char *s; - char *dest; + char *v, *dest; + for (cnt = 1, s = src; s && *s; s++) { if (*s == '\\') s++; cnt++; } - dest = xmalloc(cnt); - if (!(flags & GLOB_APPEND)) { - pglob->gl_pathv = NULL; - pglob->gl_pathc = 0; - pglob->gl_offs = 0; - pglob->gl_offs = 0; - } - pathc = ++pglob->gl_pathc; - pglob->gl_pathv = xrealloc(pglob->gl_pathv, (pathc+1) * sizeof(*pglob->gl_pathv)); - pglob->gl_pathv[pathc-1] = dest; - pglob->gl_pathv[pathc] = NULL; + v = dest = xmalloc(cnt); for (s = src; s && *s; s++, dest++) { if (*s == '\\') s++; *dest = *s; } *dest = '\0'; - return 0; + + return add_string_to_strings(strings, v); } /* XXX broken if the last character is '\\', check that before calling */ static int glob_needed(const char *s) { for (; *s; s++) { - if (*s == '\\') s++; - if (strchr("*[?", *s)) return 1; + if (*s == '\\') + s++; + if (strchr("*[?", *s)) + return 1; } return 0; } -static int xglob(o_string *dest, int flags, glob_t *pglob) +static int xglob(o_string *dest, char ***pglob) { - int gr; - /* short-circuit for null word */ /* we can code this better when the debug_printf's are gone */ if (dest->length == 0) { if (dest->nonnull) { /* bash man page calls this an "explicit" null */ - gr = globhack(dest->data, flags, pglob); - debug_printf("globhack returned %d\n", gr); - } else { - return 0; + *pglob = globhack(dest->data, *pglob); } - } else if (glob_needed(dest->data)) { - gr = glob(dest->data, flags, NULL, pglob); + return 0; + } + + if (glob_needed(dest->data)) { + glob_t globdata; + int gr; + + memset(&globdata, 0, sizeof(globdata)); + gr = glob(dest->data, 0, NULL, &globdata); debug_printf("glob returned %d\n", gr); + if (gr == GLOB_NOSPACE) + bb_error_msg_and_die("out of memory during glob"); if (gr == GLOB_NOMATCH) { - /* quote removal, or more accurately, backslash removal */ - gr = globhack(dest->data, flags, pglob); debug_printf("globhack returned %d\n", gr); + /* quote removal, or more accurately, backslash removal */ + *pglob = globhack(dest->data, *pglob); + return 0; } - } else { - gr = globhack(dest->data, flags, pglob); - debug_printf("globhack returned %d\n", gr); - } - if (gr == GLOB_NOSPACE) - bb_error_msg_and_die("out of memory during glob"); - if (gr != 0) { /* GLOB_ABORTED ? */ - bb_error_msg("glob(3) error %d", gr); + if (gr != 0) { /* GLOB_ABORTED ? */ + bb_error_msg("glob(3) error %d", gr); + } + if (globdata.gl_pathv && globdata.gl_pathv[0]) + *pglob = add_strings_to_strings(1, *pglob, globdata.gl_pathv); + /* globprint(glob_target); */ + globfree(&globdata); + return gr; } - /* globprint(glob_target); */ - return gr; + + *pglob = globhack(dest->data, *pglob); + return 0; } /* expand_strvec_to_strvec() takes a list of strings, expands @@ -2775,7 +2825,7 @@ static int setup_redirect(struct p_context *ctx, int fd, redir_type style, } redir = xzalloc(sizeof(struct redir_struct)); /* redir->next = NULL; */ - /* redir->glob_word.gl_pathv = NULL; */ + /* redir->glob_word = NULL; */ if (last_redir) { last_redir->next = redir; } else { @@ -2919,8 +2969,8 @@ static int reserved_word(o_string *dest, struct p_context *ctx) static int done_word(o_string *dest, struct p_context *ctx) { struct child_prog *child = ctx->child; - glob_t *glob_target; - int gr, flags = 0; + char ***glob_target; + int gr; debug_printf_parse("done_word entered: '%s' %p\n", dest->data, child); if (dest->length == 0 && !dest->nonnull) { @@ -2942,11 +2992,9 @@ static int done_word(o_string *dest, struct p_context *ctx) return (ctx->res_w == RES_SNTX); } } - glob_target = &child->glob_result; - if (child->argv) - flags |= GLOB_APPEND; + glob_target = &child->argv; } - gr = xglob(dest, flags, glob_target); + gr = xglob(dest, glob_target); if (gr != 0) { debug_printf_parse("done_word return 1: xglob returned %d\n", gr); return 1; @@ -2954,14 +3002,17 @@ static int done_word(o_string *dest, struct p_context *ctx) b_reset(dest); if (ctx->pending_redirect) { - ctx->pending_redirect = NULL; - if (glob_target->gl_pathc != 1) { + if (ctx->pending_redirect->glob_word + && ctx->pending_redirect->glob_word[0] + && ctx->pending_redirect->glob_word[1] + ) { + /* more than one word resulted from globbing redir */ + ctx->pending_redirect = NULL; bb_error_msg("ambiguous redirect"); debug_printf_parse("done_word return 1: ambiguous redirect\n"); return 1; } - } else { - child->argv = glob_target->gl_pathv; + ctx->pending_redirect = NULL; } #if ENABLE_HUSH_LOOPS if (ctx->res_w == RES_FOR) { @@ -3006,7 +3057,7 @@ static int done_command(struct p_context *ctx) /*child->argv = NULL;*/ /*child->is_stopped = 0;*/ /*child->group = NULL;*/ - /*child->glob_result.gl_pathv = NULL;*/ + /*child->glob_result = NULL;*/ child->family = pi; //sp: /*child->sp = 0;*/ //pt: child->parse_type = ctx->parse_type; -- 2.25.1