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Varied fixes #19

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Varied fixes #19

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df0b8fc
Use macro constant in write_val.
ericonr Jun 25, 2021
a037547
Remove erroneous dlclose call.
ericonr Jun 25, 2021
c72826e
General clean up in socket_handle.
ericonr Jun 25, 2021
86e955f
Remove unreachable conditional.
ericonr Jun 25, 2021
72dd475
Fix endianness matching.
ericonr Jun 25, 2021
7623d85
Simplify nss_getkey.
ericonr Jun 25, 2021
559c97e
Further clean up return_result.
ericonr Jun 25, 2021
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3 changes: 3 additions & 0 deletions include/nscd.h
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Original file line number Diff line number Diff line change
Expand Up @@ -39,4 +39,7 @@
#define GRMEMCNT 5
#define GR_LEN 6

#define ISPWREQ(r) (r==GETPWBYNAME || r==GETPWBYUID)
#define ISGRPREQ(r) (r==GETGRBYNAME || r==GETGRBYGID)

#endif
1 change: 0 additions & 1 deletion src/main.c
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Original file line number Diff line number Diff line change
Expand Up @@ -150,7 +150,6 @@ int main(int argc, char **argv)
if(!mod->nss_getgrgid_r) mod->nss_getgrgid_r = null_getgrgid_r;
mod->nss_initgroups_dyn = (nss_initgroups_dyn)get_fn(dll, "initgroups_dyn", service->service);
if(!mod->nss_initgroups_dyn) mod->nss_initgroups_dyn = null_initgroups_dyn;
dlclose(dll);

memcpy(mod->on_status, service->on_status, sizeof(mod->on_status));

Expand Down
62 changes: 33 additions & 29 deletions src/socket_handle.c
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Original file line number Diff line number Diff line change
Expand Up @@ -11,6 +11,8 @@
#include <semaphore.h>
#include <ctype.h>
#include <limits.h>
#include <assert.h>
#include <stdbool.h>

#include "util.h"
#include "nss.h"
Expand Down Expand Up @@ -117,12 +119,14 @@ void socket_handle(int fd, int timeout, locale_t l, void *pthread_args)
}


if(full_read(n, (char*)buf, REQ_LEN * sizeof(uint32_t)) < 0) {
if(full_read(n, (char*)buf, sizeof buf) < 0) {
syslog(LOG_ERR, "error in read: %s", strerror_l(errno, l));
goto cleanup_fd;
}

if(buf[REQVERSION] != NSCDVERSION && buf[REQVERSION] == swap32(NSCDVERSION)) {
/* means our endianness doesn't match the requester's */
swap = 1;
for(int i = 0; i < REQ_LEN; i++)
buf[i] = swap32(buf[i]);
}
Expand Down Expand Up @@ -200,36 +204,37 @@ struct initgroups_res {
gid_t *grps;
};

enum nss_status nss_getkey(uint32_t reqtype, void *fn, void *key, void *res, char *buf, size_t n, int *ret)
static enum nss_status nss_getkey(uint32_t reqtype, struct mod_passwd *mod_passwd, struct mod_group *mod_group, void *key, void *res, char *buf, size_t n, int *ret)
{
nss_getgrnam_r fn_grnam;
nss_getgrgid_r fn_grgid;
nss_getpwnam_r fn_pwnam;
nss_getpwuid_r fn_pwuid;
int retval = NSS_STATUS_UNAVAIL;
struct initgroups_res *initgroups_res;

/* for debug only: guarantee the nss_getkey function is being used correctly */
if(ISPWREQ(reqtype)) assert(mod_passwd);
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This needs a comment above it explaining that this is for debugging only.

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Added a comment now.

else assert(mod_group);

switch(reqtype) {
case GETPWBYNAME:
retval = ((nss_getpwnam_r)fn)((char*)key, (struct passwd*)res, buf, n, ret);
retval = mod_passwd->nss_getpwnam_r((char*)key, (struct passwd*)res, buf, n, ret);
break;
case GETPWBYUID:
retval = ((nss_getpwuid_r)fn)((uid_t)*(uint32_t*)key, (struct passwd*)res, buf, n, ret);
retval = mod_passwd->nss_getpwuid_r((uid_t)*(uint32_t*)key, (struct passwd*)res, buf, n, ret);
break;
case GETGRBYNAME:
retval = ((nss_getgrnam_r)fn)((char*)key, (struct group*)res, buf, n, ret);
retval = mod_group->nss_getgrnam_r((char*)key, (struct group*)res, buf, n, ret);
break;
case GETGRBYGID:
retval = ((nss_getgrgid_r)fn)((gid_t)*(uint32_t*)key, (struct group*)res, buf, n, ret);
retval = mod_group->nss_getgrgid_r((gid_t)*(uint32_t*)key, (struct group*)res, buf, n, ret);
break;
case GETINITGR:
initgroups_res = res;
initgroups_res->end = 0;
initgroups_res->alloc = NGROUPS_MAX + 1;
initgroups_res->grps = (gid_t*)malloc(sizeof(gid_t) * initgroups_res->alloc);
retval = ((nss_initgroups_dyn)fn)((char*)key, (gid_t)-1, &(initgroups_res->end), &(initgroups_res->alloc), &(initgroups_res->grps), UINT32_MAX, ret);
retval = mod_group->nss_initgroups_dyn((char*)key, (gid_t)-1, &(initgroups_res->end), &(initgroups_res->alloc), &(initgroups_res->grps), UINT32_MAX, ret);
break;
}
if(retval == NSS_STATUS_SUCCESS && (reqtype == GETPWBYNAME || reqtype == GETPWBYUID)) {
if(retval == NSS_STATUS_SUCCESS && ISPWREQ(reqtype)) {
struct passwd *pwd = res;
if(!pwd->pw_name) retval = NSS_STATUS_NOTFOUND;
#ifdef HAVE_PW_PASSWD
Expand All @@ -241,7 +246,7 @@ enum nss_status nss_getkey(uint32_t reqtype, void *fn, void *key, void *res, cha
if(!pwd->pw_dir) retval = NSS_STATUS_NOTFOUND;
if(!pwd->pw_shell) retval = NSS_STATUS_NOTFOUND;
}
if(retval == NSS_STATUS_SUCCESS && (reqtype == GETGRBYNAME || reqtype == GETGRBYGID)) {
if(retval == NSS_STATUS_SUCCESS && ISGRPREQ(reqtype)) {
struct group *grp = res;
if(!grp->gr_name) retval = NSS_STATUS_NOTFOUND;
#ifdef HAVE_GR_PASSWD
Expand All @@ -265,32 +270,31 @@ int return_result(int fd, int swap, uint32_t reqtype, void *key)
char *buf = 0;
size_t buf_len = 0;
long tmp;
void *fn;
bool using_passwd;

switch(reqtype) {
case GETPWBYNAME: case GETPWBYUID:
if(ISPWREQ(reqtype)) {
using_passwd = true;
l = list_head(&passwd_mods);
tmp = sysconf(_SC_GETPW_R_SIZE_MAX);
if(tmp < 0) buf_len = 4096;
else buf_len = tmp;
buf = malloc(buf_len);
if(!buf) return -1;
break;
case GETGRBYNAME: case GETGRBYGID: case GETINITGR:
} else {
using_passwd = false;
l = list_head(&group_mods);
tmp = sysconf(_SC_GETGR_R_SIZE_MAX);
if(tmp < 0) buf_len = 4096;
else buf_len = tmp;
buf = malloc(buf_len);
if(!buf) return -1;
break;
}
for(; l; l = list_next(l)) {
int ret;
int act;
enum nss_status status;
action *on_status;
if(reqtype == GETPWBYNAME || reqtype == GETPWBYUID) {
if(using_passwd) {
mod_passwd = list_ref(l, struct mod_passwd, link);
mod_group = 0;
} else {
Expand All @@ -299,27 +303,27 @@ int return_result(int fd, int swap, uint32_t reqtype, void *key)
}
do {
memset(&res, 0, sizeof(res));
fn =
reqtype == GETPWBYNAME ? (void*)mod_passwd->nss_getpwnam_r :
reqtype == GETPWBYUID ? (void*)mod_passwd->nss_getpwuid_r :
reqtype == GETGRBYNAME ? (void*)mod_group->nss_getgrnam_r :
reqtype == GETGRBYGID ? (void*)mod_group->nss_getgrgid_r :
(void*)mod_group->nss_initgroups_dyn;
status = nss_getkey(reqtype, fn, key, &res, buf, buf_len, &ret);
status = nss_getkey(reqtype, mod_passwd, mod_group, key, &res, buf, buf_len, &ret);
if(status == NSS_STATUS_TRYAGAIN && ret == ERANGE) {
size_t new_len;
char *new_buf;
if(ret == EAGAIN) break;
if(buf_len == SIZE_MAX) {
free(buf);
errno = ENOMEM;
return -1;
}
/* memory growth factor is 1.5x.
* to avoid overshooting SIZE_MAX and overflowing,
* we use the check below: buf_len > (2/3) * SIZE_MAX */
if(buf_len > SIZE_MAX - buf_len/2) {
new_len = SIZE_MAX;
} else {
/* buf_len * 1.5 */
new_len = buf_len + buf_len/2;
}
/* TODO: doesn't need to be a realloc,
* since we don't need to copy the memory;
* evaluate if it's better or worse than malloc+free */
new_buf = realloc(buf, new_len);
if(!new_buf) {
free(buf);
Expand All @@ -330,7 +334,7 @@ int return_result(int fd, int swap, uint32_t reqtype, void *key)
}
} while(status == NSS_STATUS_TRYAGAIN && ret == ERANGE);

on_status = mod_passwd ? mod_passwd->on_status : mod_group->on_status;
on_status = using_passwd ? mod_passwd->on_status : mod_group->on_status;
act = on_status[
status == NSS_STATUS_TRYAGAIN ? STS_TRYAGAIN :
status == NSS_STATUS_UNAVAIL ? STS_UNAVAIL :
Expand Down
2 changes: 1 addition & 1 deletion src/write_val.c
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Original file line number Diff line number Diff line change
Expand Up @@ -9,7 +9,7 @@

int write_pwd(int fd, int swap, struct passwd *pwd)
{
uint32_t head[9] = {
uint32_t head[PW_LEN] = {
NSCDVERSION
};
size_t namelen = 0, passwdlen = 0, gecoslen = 0, dirlen = 0, shelllen = 0;
Expand Down