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authorRob Landley <rob@landley.net>2018-07-04 18:49:03 -0500
committerRob Landley <rob@landley.net>2018-07-04 18:49:03 -0500
commitff2d528a0a6943bd4247f3c122c145a5b19f0387 (patch)
treee79c2baaa076a33deea48e65cf158b62ec6490da
parent4d673c9ad4c65c329a85ebb19c2812ae93183099 (diff)
downloadtoybox-ff2d528a0a6943bd4247f3c122c145a5b19f0387.tar.gz
Add xgetrandom() with probe for new system call (else open/read /dev/{,u}random)
-rw-r--r--lib/lib.c4
-rw-r--r--lib/password.c6
-rw-r--r--lib/portability.c11
-rw-r--r--lib/portability.h5
-rwxr-xr-xscripts/genconfig.sh5
-rw-r--r--toys/other/shred.c5
6 files changed, 25 insertions, 11 deletions
diff --git a/lib/lib.c b/lib/lib.c
index 88dd13a0..6d75e0f3 100644
--- a/lib/lib.c
+++ b/lib/lib.c
@@ -1144,9 +1144,7 @@ int qstrcmp(const void *a, const void *b)
void create_uuid(char *uuid)
{
// "Set all the ... bits to randomly (or pseudo-randomly) chosen values".
- int fd = xopenro("/dev/urandom");
- xreadall(fd, uuid, 16);
- close(fd);
+ xgetrandom(uuid, 16, 0);
// "Set the four most significant bits ... of the time_hi_and_version
// field to the 4-bit version number [4]".
diff --git a/lib/password.c b/lib/password.c
index eab2d669..20c2f481 100644
--- a/lib/password.c
+++ b/lib/password.c
@@ -8,7 +8,7 @@
#include "toys.h"
#include <time.h>
-// generate appropriate random salt string for given encryption algorithm.
+// generate ID prefix and random salt for given encryption algorithm.
int get_salt(char *salt, char *algo)
{
struct {
@@ -24,9 +24,7 @@ int get_salt(char *salt, char *algo)
if (al[i].id) s += sprintf(s, "$%c$", '0'+al[i].id);
// Read appropriate number of random bytes for salt
- i = xopenro("/dev/urandom");
- xreadall(i, libbuf, ((len*6)+7)/8);
- close(i);
+ xgetrandom(libbuf, ((len*6)+7)/8, 0);
// Grab 6 bit chunks and convert to characters in ./0-9a-zA-Z
for (i=0; i<len; i++) {
diff --git a/lib/portability.c b/lib/portability.c
index 38cf5cb9..c42a052e 100644
--- a/lib/portability.c
+++ b/lib/portability.c
@@ -30,6 +30,17 @@ pid_t xfork(void)
}
#endif
+void xgetrandom(void *buf, unsigned buflen, unsigned flags)
+{
+#if CFG_TOYBOX_GETRANDOM
+ if (buflen != getrandom(buf, buflen, flags)) perror_exit("getrandom");
+#else
+ int fd = xopen(flags ? "/dev/random" : "/dev/urandom", O_RDONLY);
+ xreadall(fd, buf, buflen);
+ close(fd);
+#endif
+}
+
#if defined(__APPLE__)
ssize_t getdelim(char **linep, size_t *np, int delim, FILE *stream)
{
diff --git a/lib/portability.h b/lib/portability.h
index 50c935b5..39e61810 100644
--- a/lib/portability.h
+++ b/lib/portability.h
@@ -251,3 +251,8 @@ static inline char *get_sched_policy_name(int policy) {return "unknown";}
typedef struct {char *c_name; int c_val;} CODE;
extern CODE prioritynames[], facilitynames[];
#endif
+
+#if CFG_TOYBOX_GETRANDOM
+#include <sys/random.h>
+#endif
+void xgetrandom(void *buf, unsigned len, unsigned flags);
diff --git a/scripts/genconfig.sh b/scripts/genconfig.sh
index e8df5965..533df600 100755
--- a/scripts/genconfig.sh
+++ b/scripts/genconfig.sh
@@ -105,6 +105,11 @@ EOF
struct rlimit *old_limit);
int main(int argc, char *argv[]) { prlimit(0, 0, 0, 0); }
EOF
+
+ probesymbol TOYBOX_GETRANDOM << EOF
+ #include <sys/random.h>
+ int main(void) { char buf[100]; getrandom(buf, 100, 0); }
+EOF
}
genconfig()
diff --git a/toys/other/shred.c b/toys/other/shred.c
index 30b5e7d9..e10adc09 100644
--- a/toys/other/shred.c
+++ b/toys/other/shred.c
@@ -33,8 +33,6 @@ GLOBALS(
long offset;
long iterations;
long size;
-
- int ufd;
)
void shred_main(void)
@@ -42,7 +40,6 @@ void shred_main(void)
char **try;
if (!(toys.optflags & FLAG_n)) TT.iterations++;
- TT.ufd = xopenro("/dev/urandom");
// We don't use loopfiles() here because "-" isn't stdin, and want to
// respond to files we can't open via chmod.
@@ -96,7 +93,7 @@ void shred_main(void)
if (toys.optflags & FLAG_x)
if (len-pos < throw) throw = len-pos;
- if (iter != TT.iterations) xread(TT.ufd, toybuf, throw);
+ if (iter != TT.iterations) xgetrandom(toybuf, throw, 0);
if (throw != writeall(fd, toybuf, throw)) perror_msg_raw(*try);
pos += throw;
}