From 6ef6358e5115c85b60000afef572b2bcddf8766d Mon Sep 17 00:00:00 2001 From: Geoffrey Keating Date: Thu, 21 Dec 2006 01:32:48 +0000 Subject: [PATCH] * cp-demangle.h: Add comment explaining what to do to avoid overrunning string. (d_check_char): New. (d_next_char): Don't advance past trailing '\0'. * cp-demangle.c (cplus_demangle_mangled_name): Use d_check_char. (d_nested_name): Likewise. (d_special_name): Likewise. (d_call_offset): Likewise. (d_function_type): Likewise. (d_array_type): Likewise. (d_pointer_to_member_type): Likewise. (d_template_param): Likewise. (d_template_args): Likewise. (d_template_arg): Likewise. (d_expr_primary): Likewise. (d_local_name): Likewise. (d_substitution): Likewise. (d_ctor_dtor_name): Use d_advance rather than d_next_char. * testsuite/test-demangle.c: Include sys/mman.h. (MAP_ANONYMOUS): Define. (protect_end): New. (main): Use protect_end. * testsuite/demangle-expected: Add testcases for overrunning the end of the string. --- libiberty/ChangeLog | 27 +++++++++++++++++ libiberty/cp-demangle.c | 57 +++++++++++++++++------------------ libiberty/cp-demangle.h | 8 ++++- libiberty/testsuite/demangle-expected | 22 ++++++++++++++ libiberty/testsuite/test-demangle.c | 56 +++++++++++++++++++++++++++++++--- 5 files changed, 136 insertions(+), 34 deletions(-) diff --git a/libiberty/ChangeLog b/libiberty/ChangeLog index 4b27eb0..e72f845 100644 --- a/libiberty/ChangeLog +++ b/libiberty/ChangeLog @@ -1,3 +1,30 @@ +2006-12-20 Geoffrey Keating + + * cp-demangle.h: Add comment explaining what to do to avoid + overrunning string. + (d_check_char): New. + (d_next_char): Don't advance past trailing '\0'. + * cp-demangle.c (cplus_demangle_mangled_name): Use d_check_char. + (d_nested_name): Likewise. + (d_special_name): Likewise. + (d_call_offset): Likewise. + (d_function_type): Likewise. + (d_array_type): Likewise. + (d_pointer_to_member_type): Likewise. + (d_template_param): Likewise. + (d_template_args): Likewise. + (d_template_arg): Likewise. + (d_expr_primary): Likewise. + (d_local_name): Likewise. + (d_substitution): Likewise. + (d_ctor_dtor_name): Use d_advance rather than d_next_char. + * testsuite/test-demangle.c: Include sys/mman.h. + (MAP_ANONYMOUS): Define. + (protect_end): New. + (main): Use protect_end. + * testsuite/demangle-expected: Add testcases for overrunning + the end of the string. + 2006-11-30 Andrew Stubbs J"orn Rennecke diff --git a/libiberty/cp-demangle.c b/libiberty/cp-demangle.c index 2fa5978..ac1dfe5 100644 --- a/libiberty/cp-demangle.c +++ b/libiberty/cp-demangle.c @@ -913,9 +913,9 @@ CP_STATIC_IF_GLIBCPP_V3 struct demangle_component * cplus_demangle_mangled_name (struct d_info *di, int top_level) { - if (d_next_char (di) != '_') + if (! d_check_char (di, '_')) return NULL; - if (d_next_char (di) != 'Z') + if (! d_check_char (di, 'Z')) return NULL; return d_encoding (di, top_level); } @@ -1123,7 +1123,7 @@ d_nested_name (struct d_info *di) struct demangle_component *ret; struct demangle_component **pret; - if (d_next_char (di) != 'N') + if (! d_check_char (di, 'N')) return NULL; pret = d_cv_qualifiers (di, &ret, 1); @@ -1134,7 +1134,7 @@ d_nested_name (struct d_info *di) if (*pret == NULL) return NULL; - if (d_next_char (di) != 'E') + if (! d_check_char (di, 'E')) return NULL; return ret; @@ -1449,11 +1449,8 @@ d_operator_name (struct d_info *di) static struct demangle_component * d_special_name (struct d_info *di) { - char c; - di->expansion += 20; - c = d_next_char (di); - if (c == 'T') + if (d_check_char (di, 'T')) { switch (d_next_char (di)) { @@ -1502,7 +1499,7 @@ d_special_name (struct d_info *di) offset = d_number (di); if (offset < 0) return NULL; - if (d_next_char (di) != '_') + if (! d_check_char (di, '_')) return NULL; base_type = cplus_demangle_type (di); /* We don't display the offset. FIXME: We should display @@ -1523,7 +1520,7 @@ d_special_name (struct d_info *di) return NULL; } } - else if (c == 'G') + else if (d_check_char (di, 'G')) { switch (d_next_char (di)) { @@ -1570,14 +1567,14 @@ d_call_offset (struct d_info *di, int c) else if (c == 'v') { d_number (di); - if (d_next_char (di) != '_') + if (! d_check_char (di, '_')) return 0; d_number (di); } else return 0; - if (d_next_char (di) != '_') + if (! d_check_char (di, '_')) return 0; return 1; @@ -1601,13 +1598,13 @@ d_ctor_dtor_name (struct d_info *di) else if (di->last_name->type == DEMANGLE_COMPONENT_SUB_STD) di->expansion += di->last_name->u.s_string.len; } - switch (d_next_char (di)) + switch (d_peek_char (di)) { case 'C': { enum gnu_v3_ctor_kinds kind; - switch (d_next_char (di)) + switch (d_peek_next_char (di)) { case '1': kind = gnu_v3_complete_object_ctor; @@ -1621,6 +1618,7 @@ d_ctor_dtor_name (struct d_info *di) default: return NULL; } + d_advance (di, 2); return d_make_ctor (di, kind, di->last_name); } @@ -1628,7 +1626,7 @@ d_ctor_dtor_name (struct d_info *di) { enum gnu_v3_dtor_kinds kind; - switch (d_next_char (di)) + switch (d_peek_next_char (di)) { case '0': kind = gnu_v3_deleting_dtor; @@ -1642,6 +1640,7 @@ d_ctor_dtor_name (struct d_info *di) default: return NULL; } + d_advance (di, 2); return d_make_dtor (di, kind, di->last_name); } @@ -1925,7 +1924,7 @@ d_function_type (struct d_info *di) { struct demangle_component *ret; - if (d_next_char (di) != 'F') + if (! d_check_char (di, 'F')) return NULL; if (d_peek_char (di) == 'Y') { @@ -1934,7 +1933,7 @@ d_function_type (struct d_info *di) d_advance (di, 1); } ret = d_bare_function_type (di, 1); - if (d_next_char (di) != 'E') + if (! d_check_char (di, 'E')) return NULL; return ret; } @@ -2021,7 +2020,7 @@ d_array_type (struct d_info *di) char peek; struct demangle_component *dim; - if (d_next_char (di) != 'A') + if (! d_check_char (di, 'A')) return NULL; peek = d_peek_char (di); @@ -2049,7 +2048,7 @@ d_array_type (struct d_info *di) return NULL; } - if (d_next_char (di) != '_') + if (! d_check_char (di, '_')) return NULL; return d_make_comp (di, DEMANGLE_COMPONENT_ARRAY_TYPE, dim, @@ -2065,7 +2064,7 @@ d_pointer_to_member_type (struct d_info *di) struct demangle_component *mem; struct demangle_component **pmem; - if (d_next_char (di) != 'M') + if (! d_check_char (di, 'M')) return NULL; cl = cplus_demangle_type (di); @@ -2109,7 +2108,7 @@ d_template_param (struct d_info *di) { long param; - if (d_next_char (di) != 'T') + if (! d_check_char (di, 'T')) return NULL; if (d_peek_char (di) == '_') @@ -2122,7 +2121,7 @@ d_template_param (struct d_info *di) param += 1; } - if (d_next_char (di) != '_') + if (! d_check_char (di, '_')) return NULL; ++di->did_subs; @@ -2144,7 +2143,7 @@ d_template_args (struct d_info *di) constructor or destructor. */ hold_last_name = di->last_name; - if (d_next_char (di) != 'I') + if (! d_check_char (di, 'I')) return NULL; al = NULL; @@ -2189,7 +2188,7 @@ d_template_arg (struct d_info *di) case 'X': d_advance (di, 1); ret = d_expression (di); - if (d_next_char (di) != 'E') + if (! d_check_char (di, 'E')) return NULL; return ret; @@ -2316,7 +2315,7 @@ d_expr_primary (struct d_info *di) { struct demangle_component *ret; - if (d_next_char (di) != 'L') + if (! d_check_char (di, 'L')) return NULL; if (d_peek_char (di) == '_') ret = cplus_demangle_mangled_name (di, 0); @@ -2362,7 +2361,7 @@ d_expr_primary (struct d_info *di) } ret = d_make_comp (di, t, type, d_make_name (di, s, d_str (di) - s)); } - if (d_next_char (di) != 'E') + if (! d_check_char (di, 'E')) return NULL; return ret; } @@ -2376,12 +2375,12 @@ d_local_name (struct d_info *di) { struct demangle_component *function; - if (d_next_char (di) != 'Z') + if (! d_check_char (di, 'Z')) return NULL; function = d_encoding (di, 0); - if (d_next_char (di) != 'E') + if (! d_check_char (di, 'E')) return NULL; if (d_peek_char (di) == 's') @@ -2486,7 +2485,7 @@ d_substitution (struct d_info *di, int prefix) { char c; - if (d_next_char (di) != 'S') + if (! d_check_char (di, 'S')) return NULL; c = d_next_char (di); diff --git a/libiberty/cp-demangle.h b/libiberty/cp-demangle.h index 2517a57e..920ca47 100644 --- a/libiberty/cp-demangle.h +++ b/libiberty/cp-demangle.h @@ -123,10 +123,16 @@ struct d_info int expansion; }; +/* To avoid running past the ending '\0', don't: + - call d_peek_next_char if d_peek_char returned '\0' + - call d_advance with an 'i' that is too large + - call d_check_char(di, '\0') + Everything else is safe. */ #define d_peek_char(di) (*((di)->n)) #define d_peek_next_char(di) ((di)->n[1]) #define d_advance(di, i) ((di)->n += (i)) -#define d_next_char(di) (*((di)->n++)) +#define d_check_char(di, c) (d_peek_char(di) == c ? ((di)->n++, 1) : 0) +#define d_next_char(di) (d_peek_char(di) == '\0' ? '\0' : *((di)->n++)) #define d_str(di) ((di)->n) /* Functions and arrays in cp-demangle.c which are referenced by diff --git a/libiberty/testsuite/demangle-expected b/libiberty/testsuite/demangle-expected index 3f5622f..56d9f89 100644 --- a/libiberty/testsuite/demangle-expected +++ b/libiberty/testsuite/demangle-expected @@ -3816,3 +3816,25 @@ f SASDASDFASDF_sdfsdf SASDASDFASDF_sdfsdf SASDASDFASDF_sdfsdf +# These are all cases of invalid manglings where the demangler would read +# past the end of the string. +# d_name wasn't honouring a NULL from d_substitution +--format=gnu-v3 +_ZSA +_ZSA +# d_expr_primary wasn't honouring NULL from cplus_demangle_mangled_name +--format=gnu-v3 +_ZN1fIL_ +_ZN1fIL_ +# d_operator_name was taking two characters in a row +--format=gnu-v3 +_Za +_Za +# d_prefix wasn't honouring NULL from d_substitution +--format=gnu-v3 +_ZNSA +_ZNSA +# d_prefix wasn't honouring NULL from d_template_param +--format=gnu-v3 +_ZNT +_ZNT diff --git a/libiberty/testsuite/test-demangle.c b/libiberty/testsuite/test-demangle.c index 9379399..12b07dd 100644 --- a/libiberty/testsuite/test-demangle.c +++ b/libiberty/testsuite/test-demangle.c @@ -86,6 +86,50 @@ getline(buf) buf->alloced = alloc; } +/* If we have mmap() and mprotect(), copy the string S just before a + protected page, so that if the demangler runs over the end of the + string we'll get a fault, and return the address of the new string. + If no mmap, or it fails, or it looks too hard, just return S. */ + +#ifdef HAVE_SYS_MMAN_H +#include +#endif +#if defined(MAP_ANON) && ! defined (MAP_ANONYMOUS) +#define MAP_ANONYMOUS MAP_ANON +#endif + +static const char * +protect_end (const char * s) +{ +#if defined(HAVE_MMAP) && defined (MAP_ANONYMOUS) + size_t pagesize = getpagesize(); + static char * buf; + size_t s_len = strlen (s); + char * result; + + /* Don't try if S is too long. */ + if (s_len >= pagesize) + return s; + + /* Allocate one page of allocated space followed by an unmapped + page. */ + if (buf == NULL) + { + buf = mmap (NULL, pagesize * 2, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + if (! buf) + return s; + munmap (buf + pagesize, pagesize); + } + + result = buf + (pagesize - s_len - 1); + memcpy (result, s, s_len + 1); + return result; +#else + return s; +#endif +} + static void fail (lineno, opts, in, out, exp) int lineno; @@ -150,6 +194,8 @@ main(argc, argv) for (;;) { + const char *inp; + getline (&format); if (feof (stdin)) break; @@ -157,6 +203,8 @@ main(argc, argv) getline (&input); getline (&expect); + inp = protect_end (input.data); + tests++; no_params = 0; @@ -237,14 +285,14 @@ main(argc, argv) { enum gnu_v3_ctor_kinds kc; - kc = is_gnu_v3_mangled_ctor (input.data); + kc = is_gnu_v3_mangled_ctor (inp); sprintf (buf, "%d", (int) kc); } else { enum gnu_v3_dtor_kinds kd; - kd = is_gnu_v3_mangled_dtor (input.data); + kd = is_gnu_v3_mangled_dtor (inp); sprintf (buf, "%d", (int) kd); } @@ -259,7 +307,7 @@ main(argc, argv) cplus_demangle_set_style (style); - result = cplus_demangle (input.data, + result = cplus_demangle (inp, DMGL_PARAMS|DMGL_ANSI|DMGL_TYPES |(ret_postfix ? DMGL_RET_POSTFIX : 0)); @@ -275,7 +323,7 @@ main(argc, argv) if (no_params) { getline (&expect); - result = cplus_demangle (input.data, DMGL_ANSI|DMGL_TYPES); + result = cplus_demangle (inp, DMGL_ANSI|DMGL_TYPES); if (result ? strcmp (result, expect.data) -- 2.7.4