From 1181551ef0a9a7f611a3d1130d2b284280882870 Mon Sep 17 00:00:00 2001 From: Nick Clifton Date: Thu, 12 Jan 2017 14:56:13 +0000 Subject: [PATCH] Prevent internal assembler errors if a stabs creation function builds an badly formatted input string. * read.c (temp_ilp): New function. Installs a temporary input line pointer. (restore_ilp): New function. Restores the original input line pointer. * read.h (temp_ilp): Prototype. (restore_ilp): Prototype. * stabs.c (dot_func_p): Use bfd_boolean type. (generate_asm_file): Use temp_ilp and restore_ilp. (stabs_generate_asm_lineno): Likewise. (stabs_generate_asm_endfunc): Likewise. --- gas/ChangeLog | 13 +++++++++++++ gas/read.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ gas/read.h | 2 ++ gas/stabs.c | 47 ++++++++++++++++++++++------------------------- 4 files changed, 81 insertions(+), 25 deletions(-) diff --git a/gas/ChangeLog b/gas/ChangeLog index 580cc18bc3..40cfce1532 100644 --- a/gas/ChangeLog +++ b/gas/ChangeLog @@ -1,3 +1,16 @@ +2017-01-12 Nick Clifton + + * read.c (temp_ilp): New function. Installs a temporary input + line pointer. + (restore_ilp): New function. Restores the original input line + pointer. + * read.h (temp_ilp): Prototype. + (restore_ilp): Prototype. + * stabs.c (dot_func_p): Use bfd_boolean type. + (generate_asm_file): Use temp_ilp and restore_ilp. + (stabs_generate_asm_lineno): Likewise. + (stabs_generate_asm_endfunc): Likewise. + 2017-01-11 Jeremy Soller * configure.tgt: Add entry for i386-redox. diff --git a/gas/read.c b/gas/read.c index 3669b285af..4ca8b010e3 100644 --- a/gas/read.c +++ b/gas/read.c @@ -6333,3 +6333,47 @@ find_end_of_line (char *s, int mri_string) { return _find_end_of_line (s, mri_string, 0, 0); } + +static char *saved_ilp = NULL; +static char *saved_limit; + +/* Use BUF as a temporary input pointer for calling other functions in this + file. BUF must be a C string, so that its end can be found by strlen. + Also sets the buffer_limit variable (local to this file) so that buffer + overruns should not occur. Saves the current input line pointer so that + it can be restored by calling restore_ilp(). + + Does not support recursion. + + FIXME: This function is currently only used by stabs.c but that + should be extended to other files in the gas source directory. */ + +void +temp_ilp (char *buf) +{ + gas_assert (saved_ilp == NULL); + gas_assert (buf != NULL); + + saved_ilp = input_line_pointer; + saved_limit = buffer_limit; + /* Prevent the assert in restore_ilp from triggering if + the input_line_pointer has not yet been initialised. */ + if (saved_ilp == NULL) + saved_limit = saved_ilp = (char *) ""; + + input_line_pointer = buf; + buffer_limit = buf + strlen (buf); +} + +/* Restore a saved input line pointer. */ + +void +restore_ilp (void) +{ + gas_assert (saved_ilp != NULL); + + input_line_pointer = saved_ilp; + buffer_limit = saved_limit; + + saved_ilp = NULL; +} diff --git a/gas/read.h b/gas/read.h index f1ccf92d6b..e83118fd69 100644 --- a/gas/read.h +++ b/gas/read.h @@ -213,3 +213,5 @@ extern void s_xstab (int what); extern void s_rva (int); extern void s_incbin (int); extern void s_weakref (int); +extern void temp_ilp (char *); +extern void restore_ilp (void); diff --git a/gas/stabs.c b/gas/stabs.c index 49fc09be75..f9127f0d5a 100644 --- a/gas/stabs.c +++ b/gas/stabs.c @@ -46,13 +46,13 @@ static void generate_asm_file (int, const char *); #define STAB_STRING_SECTION_NAME ".stabstr" #endif -/* Non-zero if we're in the middle of a .func function, in which case +/* True if we're in the middle of a .func function, in which case stabs_generate_asm_lineno emits function relative line number stabs. Otherwise it emits line number stabs with absolute addresses. Note that both cases only apply to assembler code assembled with -gstabs. */ -static int in_dot_func_p; +static bfd_boolean in_dot_func_p = FALSE; -/* Label at start of current function if in_dot_func_p != 0. */ +/* Label at start of current function if in_dot_func_p != FALSE. */ static const char *current_function_label; /* @@ -510,7 +510,6 @@ generate_asm_file (int type, const char *file) { static char *last_file; static int label_count; - char *hold; char sym[30]; char *buf; const char *tmp = file; @@ -525,8 +524,6 @@ generate_asm_file (int type, const char *file) generate a string and then parse it again. That lets us use the existing stabs hook, which expect to see a string, rather than inventing new ones. */ - hold = input_line_pointer; - sprintf (sym, "%sF%d", FAKE_LABEL_NAME, label_count); ++label_count; @@ -556,8 +553,10 @@ generate_asm_file (int type, const char *file) sprintf (bufp, "\",%d,0,0,%s\n", type, sym); - input_line_pointer = buf; + temp_ilp (buf); s_stab ('s'); + restore_ilp (); + colon (sym); if (last_file != NULL) @@ -565,8 +564,6 @@ generate_asm_file (int type, const char *file) last_file = xstrdup (file); free (buf); - - input_line_pointer = hold; } /* Generate stabs debugging information for the current line. This is @@ -576,7 +573,6 @@ void stabs_generate_asm_lineno (void) { static int label_count; - char *hold; const char *file; unsigned int lineno; char *buf; @@ -590,8 +586,6 @@ stabs_generate_asm_lineno (void) existing stabs hook, which expect to see a string, rather than inventing new ones. */ - hold = input_line_pointer; - file = as_where (&lineno); /* Don't emit sequences of stabs for the same line. */ @@ -638,11 +632,13 @@ stabs_generate_asm_lineno (void) buf = XNEWVEC (char, 100); sprintf (buf, "%d,0,%d,%s\n", N_SLINE, lineno, sym); } - input_line_pointer = buf; + + temp_ilp (buf); s_stab ('n'); + restore_ilp (); + colon (sym); - input_line_pointer = hold; outputting_stabs_line_debug = 0; free (buf); } @@ -653,29 +649,30 @@ stabs_generate_asm_lineno (void) void stabs_generate_asm_func (const char *funcname, const char *startlabname) { - static int void_emitted_p; - char *hold = input_line_pointer; + static bfd_boolean void_emitted_p = FALSE; char *buf; unsigned int lineno; if (! void_emitted_p) { - input_line_pointer = (char *) "\"void:t1=1\",128,0,0,0"; + temp_ilp ((char *) "\"void:t1=1\",128,0,0,0"); s_stab ('s'); - void_emitted_p = 1; + restore_ilp (); + void_emitted_p = TRUE; } as_where (&lineno); if (asprintf (&buf, "\"%s:F1\",%d,0,%d,%s", funcname, N_FUN, lineno + 1, startlabname) == -1) as_fatal ("%s", xstrerror (errno)); - input_line_pointer = buf; + + temp_ilp (buf); s_stab ('s'); + restore_ilp (); free (buf); - input_line_pointer = hold; current_function_label = xstrdup (startlabname); - in_dot_func_p = 1; + in_dot_func_p = TRUE; } /* Emit a stab to record the end of a function. */ @@ -685,7 +682,6 @@ stabs_generate_asm_endfunc (const char *funcname ATTRIBUTE_UNUSED, const char *startlabname) { static int label_count; - char *hold = input_line_pointer; char *buf; char sym[30]; @@ -695,11 +691,12 @@ stabs_generate_asm_endfunc (const char *funcname ATTRIBUTE_UNUSED, if (asprintf (&buf, "\"\",%d,0,0,%s-%s", N_FUN, sym, startlabname) == -1) as_fatal ("%s", xstrerror (errno)); - input_line_pointer = buf; + + temp_ilp (buf); s_stab ('s'); + restore_ilp (); free (buf); - input_line_pointer = hold; - in_dot_func_p = 0; + in_dot_func_p = FALSE; current_function_label = NULL; } -- 2.34.1