[PATCH 1/7] modpost: add strict white-listing when referencing sections.

From: Quentin Casasnovas
Date: Tue Mar 17 2015 - 08:38:45 EST


Prints a warning when a section references a section outside a strict
white-list. This will be useful to print a warning if __ex_table
references a non-executable section.

Signed-off-by: Quentin Casasnovas <quentin.casasnovas@xxxxxxxxxx>
---
scripts/mod/modpost.c | 34 +++++++++++++++++++---------------
1 file changed, 19 insertions(+), 15 deletions(-)

diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index d439856..7094a57 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -925,7 +925,8 @@ enum mismatch {

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];
};
@@ -936,19 +937,19 @@ static const struct sectioncheck sectioncheck[] = {
*/
{
.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",
@@ -957,54 +958,54 @@ 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 },
}
@@ -1018,9 +1019,12 @@ static const struct sectioncheck *section_mismatch(
const struct sectioncheck *check = &sectioncheck[0];

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;
--
2.0.5

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