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-rw-r--r--scripts/mod/modpost.c341
1 files changed, 287 insertions, 54 deletions
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index d439856f8176..91ee1b2e0f9a 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -776,6 +776,7 @@ static const char *sech_name(struct elf_info *elf, Elf_Shdr *sechdr)
* "foo" will match an exact string equal to "foo"
* "*foo" will match a string that ends with "foo"
* "foo*" will match a string that begins with "foo"
+ * "*foo*" will match a string that contains "foo"
*/
static int match(const char *sym, const char * const pat[])
{
@@ -784,8 +785,17 @@ static int match(const char *sym, const char * const pat[])
p = *pat++;
const char *endp = p + strlen(p) - 1;
+ /* "*foo*" */
+ if (*p == '*' && *endp == '*') {
+ char *here, *bare = strndup(p + 1, strlen(p) - 2);
+
+ here = strstr(sym, bare);
+ free(bare);
+ if (here != NULL)
+ return 1;
+ }
/* "*foo" */
- if (*p == '*') {
+ else if (*p == '*') {
if (strrcmp(sym, p + 1) == 0)
return 1;
}
@@ -873,7 +883,10 @@ static void check_section(const char *modname, struct elf_info *elf,
#define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS
#define DATA_SECTIONS ".data", ".data.rel"
-#define TEXT_SECTIONS ".text", ".text.unlikely"
+#define TEXT_SECTIONS ".text", ".text.unlikely", ".sched.text", \
+ ".kprobes.text"
+#define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
+ ".fixup", ".entry.text", ".exception.text", ".text.*"
#define INIT_SECTIONS ".init.*"
#define MEM_INIT_SECTIONS ".meminit.*"
@@ -881,6 +894,9 @@ static void check_section(const char *modname, struct elf_info *elf,
#define EXIT_SECTIONS ".exit.*"
#define MEM_EXIT_SECTIONS ".memexit.*"
+#define ALL_TEXT_SECTIONS ALL_INIT_TEXT_SECTIONS, ALL_EXIT_TEXT_SECTIONS, \
+ TEXT_SECTIONS, OTHER_TEXT_SECTIONS
+
/* init data sections */
static const char *const init_data_sections[] =
{ ALL_INIT_DATA_SECTIONS, NULL };
@@ -892,6 +908,9 @@ static const char *const init_sections[] = { ALL_INIT_SECTIONS, NULL };
static const char *const init_exit_sections[] =
{ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
+/* all text sections */
+static const char *const text_sections[] = { ALL_TEXT_SECTIONS, NULL };
+
/* data section */
static const char *const data_sections[] = { DATA_SECTIONS, NULL };
@@ -910,6 +929,7 @@ static const char *const data_sections[] = { DATA_SECTIONS, NULL };
static const char *const head_sections[] = { ".head.text*", NULL };
static const char *const linker_symbols[] =
{ "__init_begin", "_sinittext", "_einittext", NULL };
+static const char *const optim_symbols[] = { "*.constprop.*", NULL };
enum mismatch {
TEXT_TO_ANY_INIT,
@@ -921,34 +941,65 @@ enum mismatch {
ANY_INIT_TO_ANY_EXIT,
ANY_EXIT_TO_ANY_INIT,
EXPORT_TO_INIT_EXIT,
+ EXTABLE_TO_NON_TEXT,
};
+/**
+ * Describe how to match sections on different criterias:
+ *
+ * @fromsec: Array of sections to be matched.
+ *
+ * @bad_tosec: Relocations applied to a section in @fromsec to a section in
+ * this array is forbidden (black-list). Can be empty.
+ *
+ * @good_tosec: Relocations applied to a section in @fromsec must be
+ * targetting sections in this array (white-list). Can be empty.
+ *
+ * @mismatch: Type of mismatch.
+ *
+ * @symbol_white_list: Do not match a relocation to a symbol in this list
+ * even if it is targetting a section in @bad_to_sec.
+ *
+ * @handler: Specific handler to call when a match is found. If NULL,
+ * default_mismatch_handler() will be called.
+ *
+ */
struct sectioncheck {
const char *fromsec[20];
- const char *tosec[20];
+ const char *bad_tosec[20];
+ const char *good_tosec[20];
enum mismatch mismatch;
const char *symbol_white_list[20];
+ void (*handler)(const char *modname, struct elf_info *elf,
+ const struct sectioncheck* const mismatch,
+ Elf_Rela *r, Elf_Sym *sym, const char *fromsec);
+
};
+static void extable_mismatch_handler(const char *modname, struct elf_info *elf,
+ const struct sectioncheck* const mismatch,
+ Elf_Rela *r, Elf_Sym *sym,
+ const char *fromsec);
+
static const struct sectioncheck sectioncheck[] = {
/* Do not reference init/exit code/data from
* normal code and data
*/
{
.fromsec = { TEXT_SECTIONS, NULL },
- .tosec = { ALL_INIT_SECTIONS, NULL },
+ .bad_tosec = { ALL_INIT_SECTIONS, NULL },
.mismatch = TEXT_TO_ANY_INIT,
.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
},
{
.fromsec = { DATA_SECTIONS, NULL },
- .tosec = { ALL_XXXINIT_SECTIONS, NULL },
+ .bad_tosec = { ALL_XXXINIT_SECTIONS, NULL },
.mismatch = DATA_TO_ANY_INIT,
.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
},
{
.fromsec = { DATA_SECTIONS, NULL },
- .tosec = { INIT_SECTIONS, NULL },
+ .bad_tosec = { INIT_SECTIONS, NULL },
.mismatch = DATA_TO_ANY_INIT,
.symbol_white_list = {
"*_template", "*_timer", "*_sht", "*_ops",
@@ -957,56 +1008,66 @@ static const struct sectioncheck sectioncheck[] = {
},
{
.fromsec = { TEXT_SECTIONS, NULL },
- .tosec = { ALL_EXIT_SECTIONS, NULL },
+ .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
.mismatch = TEXT_TO_ANY_EXIT,
.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
},
{
.fromsec = { DATA_SECTIONS, NULL },
- .tosec = { ALL_EXIT_SECTIONS, NULL },
+ .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
.mismatch = DATA_TO_ANY_EXIT,
.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
},
/* Do not reference init code/data from meminit code/data */
{
.fromsec = { ALL_XXXINIT_SECTIONS, NULL },
- .tosec = { INIT_SECTIONS, NULL },
+ .bad_tosec = { INIT_SECTIONS, NULL },
.mismatch = XXXINIT_TO_SOME_INIT,
.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
},
/* Do not reference exit code/data from memexit code/data */
{
.fromsec = { ALL_XXXEXIT_SECTIONS, NULL },
- .tosec = { EXIT_SECTIONS, NULL },
+ .bad_tosec = { EXIT_SECTIONS, NULL },
.mismatch = XXXEXIT_TO_SOME_EXIT,
.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
},
/* Do not use exit code/data from init code */
{
.fromsec = { ALL_INIT_SECTIONS, NULL },
- .tosec = { ALL_EXIT_SECTIONS, NULL },
+ .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
.mismatch = ANY_INIT_TO_ANY_EXIT,
.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
},
/* Do not use init code/data from exit code */
{
.fromsec = { ALL_EXIT_SECTIONS, NULL },
- .tosec = { ALL_INIT_SECTIONS, NULL },
+ .bad_tosec = { ALL_INIT_SECTIONS, NULL },
.mismatch = ANY_EXIT_TO_ANY_INIT,
.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
},
{
.fromsec = { ALL_PCI_INIT_SECTIONS, NULL },
- .tosec = { INIT_SECTIONS, NULL },
+ .bad_tosec = { INIT_SECTIONS, NULL },
.mismatch = ANY_INIT_TO_ANY_EXIT,
.symbol_white_list = { NULL },
},
/* Do not export init/exit functions or data */
{
.fromsec = { "__ksymtab*", NULL },
- .tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
+ .bad_tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
.mismatch = EXPORT_TO_INIT_EXIT,
.symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
+},
+{
+ .fromsec = { "__ex_table", NULL },
+ /* If you're adding any new black-listed sections in here, consider
+ * adding a special 'printer' for them in scripts/check_extable.
+ */
+ .bad_tosec = { ".altinstr_replacement", NULL },
+ .good_tosec = {ALL_TEXT_SECTIONS , NULL},
+ .mismatch = EXTABLE_TO_NON_TEXT,
+ .handler = extable_mismatch_handler,
}
};
@@ -1017,10 +1078,22 @@ static const struct sectioncheck *section_mismatch(
int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
const struct sectioncheck *check = &sectioncheck[0];
+ /*
+ * The target section could be the SHT_NUL section when we're
+ * handling relocations to un-resolved symbols, trying to match it
+ * doesn't make much sense and causes build failures on parisc and
+ * mn10300 architectures.
+ */
+ if (*tosec == '\0')
+ return NULL;
+
for (i = 0; i < elems; i++) {
- if (match(fromsec, check->fromsec) &&
- match(tosec, check->tosec))
- return check;
+ if (match(fromsec, check->fromsec)) {
+ if (check->bad_tosec[0] && match(tosec, check->bad_tosec))
+ return check;
+ if (check->good_tosec[0] && !match(tosec, check->good_tosec))
+ return check;
+ }
check++;
}
return NULL;
@@ -1067,6 +1140,17 @@ static const struct sectioncheck *section_mismatch(
* This pattern is identified by
* refsymname = __init_begin, _sinittext, _einittext
*
+ * Pattern 5:
+ * GCC may optimize static inlines when fed constant arg(s) resulting
+ * in functions like cpumask_empty() -- generating an associated symbol
+ * cpumask_empty.constprop.3 that appears in the audit. If the const that
+ * is passed in comes from __init, like say nmi_ipi_mask, we get a
+ * meaningless section warning. May need to add isra symbols too...
+ * This pattern is identified by
+ * tosec = init section
+ * fromsec = text section
+ * refsymname = *.constprop.*
+ *
**/
static int secref_whitelist(const struct sectioncheck *mismatch,
const char *fromsec, const char *fromsym,
@@ -1099,6 +1183,12 @@ static int secref_whitelist(const struct sectioncheck *mismatch,
if (match(tosym, linker_symbols))
return 0;
+ /* Check for pattern 5 */
+ if (match(fromsec, text_sections) &&
+ match(tosec, init_sections) &&
+ match(fromsym, optim_symbols))
+ return 0;
+
return 1;
}
@@ -1261,6 +1351,15 @@ static void print_section_list(const char * const list[20])
fprintf(stderr, "\n");
}
+static inline void get_pretty_name(int is_func, const char** name, const char** name_p)
+{
+ switch (is_func) {
+ case 0: *name = "variable"; *name_p = ""; break;
+ case 1: *name = "function"; *name_p = "()"; break;
+ default: *name = "(unknown reference)"; *name_p = ""; break;
+ }
+}
+
/*
* Print a warning about a section mismatch.
* Try to find symbols near it so user can find it.
@@ -1280,21 +1379,13 @@ static void report_sec_mismatch(const char *modname,
char *prl_from;
char *prl_to;
- switch (from_is_func) {
- case 0: from = "variable"; from_p = ""; break;
- case 1: from = "function"; from_p = "()"; break;
- default: from = "(unknown reference)"; from_p = ""; break;
- }
- switch (to_is_func) {
- case 0: to = "variable"; to_p = ""; break;
- case 1: to = "function"; to_p = "()"; break;
- default: to = "(unknown reference)"; to_p = ""; break;
- }
-
sec_mismatch_count++;
if (!sec_mismatch_verbose)
return;
+ get_pretty_name(from_is_func, &from, &from_p);
+ get_pretty_name(to_is_func, &to, &to_p);
+
warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
"to the %s %s:%s%s\n",
modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
@@ -1408,41 +1499,179 @@ static void report_sec_mismatch(const char *modname,
tosym, prl_to, prl_to, tosym);
free(prl_to);
break;
+ case EXTABLE_TO_NON_TEXT:
+ fatal("There's a special handler for this mismatch type, "
+ "we should never get here.");
+ break;
}
fprintf(stderr, "\n");
}
-static void check_section_mismatch(const char *modname, struct elf_info *elf,
- Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
+static void default_mismatch_handler(const char *modname, struct elf_info *elf,
+ const struct sectioncheck* const mismatch,
+ Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
{
const char *tosec;
- const struct sectioncheck *mismatch;
+ Elf_Sym *to;
+ Elf_Sym *from;
+ const char *tosym;
+ const char *fromsym;
+
+ from = find_elf_symbol2(elf, r->r_offset, fromsec);
+ fromsym = sym_name(elf, from);
+
+ if (!strncmp(fromsym, "reference___initcall",
+ sizeof("reference___initcall")-1))
+ return;
tosec = sec_name(elf, get_secindex(elf, sym));
- mismatch = section_mismatch(fromsec, tosec);
+ to = find_elf_symbol(elf, r->r_addend, sym);
+ tosym = sym_name(elf, to);
+
+ /* check whitelist - we may ignore it */
+ if (secref_whitelist(mismatch,
+ fromsec, fromsym, tosec, tosym)) {
+ report_sec_mismatch(modname, mismatch,
+ fromsec, r->r_offset, fromsym,
+ is_function(from), tosec, tosym,
+ is_function(to));
+ }
+}
+
+static int is_executable_section(struct elf_info* elf, unsigned int section_index)
+{
+ if (section_index > elf->num_sections)
+ fatal("section_index is outside elf->num_sections!\n");
+
+ return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR);
+}
+
+/*
+ * We rely on a gross hack in section_rel[a]() calling find_extable_entry_size()
+ * to know the sizeof(struct exception_table_entry) for the target architecture.
+ */
+static unsigned int extable_entry_size = 0;
+static void find_extable_entry_size(const char* const sec, const Elf_Rela* r)
+{
+ /*
+ * If we're currently checking the second relocation within __ex_table,
+ * that relocation offset tells us the offsetof(struct
+ * exception_table_entry, fixup) which is equal to sizeof(struct
+ * exception_table_entry) divided by two. We use that to our advantage
+ * since there's no portable way to get that size as every architecture
+ * seems to go with different sized types. Not pretty but better than
+ * hard-coding the size for every architecture..
+ */
+ if (!extable_entry_size)
+ extable_entry_size = r->r_offset * 2;
+}
+
+static inline bool is_extable_fault_address(Elf_Rela *r)
+{
+ /*
+ * extable_entry_size is only discovered after we've handled the
+ * _second_ relocation in __ex_table, so only abort when we're not
+ * handling the first reloc and extable_entry_size is zero.
+ */
+ if (r->r_offset && extable_entry_size == 0)
+ fatal("extable_entry size hasn't been discovered!\n");
+
+ return ((r->r_offset == 0) ||
+ (r->r_offset % extable_entry_size == 0));
+}
+
+#define is_second_extable_reloc(Start, Cur, Sec) \
+ (((Cur) == (Start) + 1) && (strcmp("__ex_table", (Sec)) == 0))
+
+static void report_extable_warnings(const char* modname, struct elf_info* elf,
+ const struct sectioncheck* const mismatch,
+ Elf_Rela* r, Elf_Sym* sym,
+ const char* fromsec, const char* tosec)
+{
+ Elf_Sym* fromsym = find_elf_symbol2(elf, r->r_offset, fromsec);
+ const char* fromsym_name = sym_name(elf, fromsym);
+ Elf_Sym* tosym = find_elf_symbol(elf, r->r_addend, sym);
+ const char* tosym_name = sym_name(elf, tosym);
+ const char* from_pretty_name;
+ const char* from_pretty_name_p;
+ const char* to_pretty_name;
+ const char* to_pretty_name_p;
+
+ get_pretty_name(is_function(fromsym),
+ &from_pretty_name, &from_pretty_name_p);
+ get_pretty_name(is_function(tosym),
+ &to_pretty_name, &to_pretty_name_p);
+
+ warn("%s(%s+0x%lx): Section mismatch in reference"
+ " from the %s %s%s to the %s %s:%s%s\n",
+ modname, fromsec, (long)r->r_offset, from_pretty_name,
+ fromsym_name, from_pretty_name_p,
+ to_pretty_name, tosec, tosym_name, to_pretty_name_p);
+
+ if (!match(tosec, mismatch->bad_tosec) &&
+ is_executable_section(elf, get_secindex(elf, sym)))
+ fprintf(stderr,
+ "The relocation at %s+0x%lx references\n"
+ "section \"%s\" which is not in the list of\n"
+ "authorized sections. If you're adding a new section\n"
+ "and/or if this reference is valid, add \"%s\" to the\n"
+ "list of authorized sections to jump to on fault.\n"
+ "This can be achieved by adding \"%s\" to \n"
+ "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n",
+ fromsec, (long)r->r_offset, tosec, tosec, tosec);
+}
+
+static void extable_mismatch_handler(const char* modname, struct elf_info *elf,
+ const struct sectioncheck* const mismatch,
+ Elf_Rela* r, Elf_Sym* sym,
+ const char *fromsec)
+{
+ const char* tosec = sec_name(elf, get_secindex(elf, sym));
+
+ sec_mismatch_count++;
+
+ if (sec_mismatch_verbose)
+ report_extable_warnings(modname, elf, mismatch, r, sym,
+ fromsec, tosec);
+
+ if (match(tosec, mismatch->bad_tosec))
+ fatal("The relocation at %s+0x%lx references\n"
+ "section \"%s\" which is black-listed.\n"
+ "Something is seriously wrong and should be fixed.\n"
+ "You might get more information about where this is\n"
+ "coming from by using scripts/check_extable.sh %s\n",
+ fromsec, (long)r->r_offset, tosec, modname);
+ else if (!is_executable_section(elf, get_secindex(elf, sym))) {
+ if (is_extable_fault_address(r))
+ fatal("The relocation at %s+0x%lx references\n"
+ "section \"%s\" which is not executable, IOW\n"
+ "it is not possible for the kernel to fault\n"
+ "at that address. Something is seriously wrong\n"
+ "and should be fixed.\n",
+ fromsec, (long)r->r_offset, tosec);
+ else
+ fatal("The relocation at %s+0x%lx references\n"
+ "section \"%s\" which is not executable, IOW\n"
+ "the kernel will fault if it ever tries to\n"
+ "jump to it. Something is seriously wrong\n"
+ "and should be fixed.\n",
+ fromsec, (long)r->r_offset, tosec);
+ }
+}
+
+static void check_section_mismatch(const char *modname, struct elf_info *elf,
+ Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
+{
+ const char *tosec = sec_name(elf, get_secindex(elf, sym));;
+ const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec);
+
if (mismatch) {
- Elf_Sym *to;
- Elf_Sym *from;
- const char *tosym;
- const char *fromsym;
-
- from = find_elf_symbol2(elf, r->r_offset, fromsec);
- fromsym = sym_name(elf, from);
- to = find_elf_symbol(elf, r->r_addend, sym);
- tosym = sym_name(elf, to);
-
- if (!strncmp(fromsym, "reference___initcall",
- sizeof("reference___initcall")-1))
- return;
-
- /* check whitelist - we may ignore it */
- if (secref_whitelist(mismatch,
- fromsec, fromsym, tosec, tosym)) {
- report_sec_mismatch(modname, mismatch,
- fromsec, r->r_offset, fromsym,
- is_function(from), tosec, tosym,
- is_function(to));
- }
+ if (mismatch->handler)
+ mismatch->handler(modname, elf, mismatch,
+ r, sym, fromsec);
+ else
+ default_mismatch_handler(modname, elf, mismatch,
+ r, sym, fromsec);
}
}
@@ -1582,6 +1811,8 @@ static void section_rela(const char *modname, struct elf_info *elf,
/* Skip special sections */
if (is_shndx_special(sym->st_shndx))
continue;
+ if (is_second_extable_reloc(start, rela, fromsec))
+ find_extable_entry_size(fromsec, &r);
check_section_mismatch(modname, elf, &r, sym, fromsec);
}
}
@@ -1640,6 +1871,8 @@ static void section_rel(const char *modname, struct elf_info *elf,
/* Skip special sections */
if (is_shndx_special(sym->st_shndx))
continue;
+ if (is_second_extable_reloc(start, rel, fromsec))
+ find_extable_entry_size(fromsec, &r);
check_section_mismatch(modname, elf, &r, sym, fromsec);
}
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-19 00:07:33 +0000