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-rw-r--r--src/shared/ask-password-api.c2
-rw-r--r--src/shared/hashmap.c104
-rw-r--r--src/shared/hashmap.h10
-rw-r--r--src/shared/siphash24.c135
-rw-r--r--src/shared/siphash24.h6
-rw-r--r--src/shared/util.c60
-rw-r--r--src/shared/util.h15
7 files changed, 245 insertions, 87 deletions
diff --git a/src/shared/ask-password-api.c b/src/shared/ask-password-api.c
index 755abf0b5e..c9c82b2520 100644
--- a/src/shared/ask-password-api.c
+++ b/src/shared/ask-password-api.c
@@ -262,7 +262,7 @@ static int create_socket(char **name) {
return -errno;
}
- snprintf(sa.un.sun_path, sizeof(sa.un.sun_path)-1, "/run/systemd/ask-password/sck.%llu", random_ull());
+ snprintf(sa.un.sun_path, sizeof(sa.un.sun_path)-1, "/run/systemd/ask-password/sck.%" PRIx64, random_u64());
RUN_WITH_UMASK(0177) {
r = bind(fd, &sa.sa, offsetof(struct sockaddr_un, sun_path) + strlen(sa.un.sun_path));
diff --git a/src/shared/hashmap.c b/src/shared/hashmap.c
index 3762e3ab0d..b1dccaf4e7 100644
--- a/src/shared/hashmap.c
+++ b/src/shared/hashmap.c
@@ -24,13 +24,10 @@
#include <string.h>
#include <errno.h>
-#ifdef HAVE_SYS_AUXV_H
-#include <sys/auxv.h>
-#endif
-
#include "util.h"
#include "hashmap.h"
#include "macro.h"
+#include "siphash24.h"
#define INITIAL_N_BUCKETS 31
@@ -50,8 +47,8 @@ struct Hashmap {
struct hashmap_entry ** buckets;
unsigned n_buckets, n_entries;
- unsigned random_xor;
- bool from_pool;
+ uint8_t hash_key[HASH_KEY_SIZE];
+ bool from_pool:1;
};
struct pool {
@@ -134,51 +131,60 @@ __attribute__((destructor)) static void cleanup_pool(void) {
#endif
-unsigned string_hash_func(const void *p) {
- unsigned hash = 5381;
- const signed char *c;
-
- /* DJB's hash function */
-
- for (c = p; *c; c++)
- hash = (hash << 5) + hash + (unsigned) *c;
-
- return hash;
+unsigned long string_hash_func(const void *p, const uint8_t hash_key[HASH_KEY_SIZE]) {
+ uint64_t u;
+ siphash24((uint8_t*) &u, p, strlen(p), hash_key);
+ return (unsigned long) u;
}
int string_compare_func(const void *a, const void *b) {
return strcmp(a, b);
}
-unsigned trivial_hash_func(const void *p) {
- return PTR_TO_UINT(p);
+unsigned long trivial_hash_func(const void *p, const uint8_t hash_key[HASH_KEY_SIZE]) {
+ uint64_t u;
+ siphash24((uint8_t*) &u, &p, sizeof(p), hash_key);
+ return (unsigned long) u;
}
int trivial_compare_func(const void *a, const void *b) {
return a < b ? -1 : (a > b ? 1 : 0);
}
-unsigned uint64_hash_func(const void *p) {
+unsigned long uint64_hash_func(const void *p, const uint8_t hash_key[HASH_KEY_SIZE]) {
uint64_t u;
-
- assert_cc(sizeof(uint64_t) == 2*sizeof(unsigned));
-
- u = *(const uint64_t*) p;
-
- return (unsigned) ((u >> 32) ^ u);
+ siphash24((uint8_t*) &u, p, sizeof(uint64_t), hash_key);
+ return (unsigned long) u;
}
int uint64_compare_func(const void *_a, const void *_b) {
uint64_t a, b;
-
a = *(const uint64_t*) _a;
b = *(const uint64_t*) _b;
-
return a < b ? -1 : (a > b ? 1 : 0);
}
static unsigned bucket_hash(Hashmap *h, const void *p) {
- return (h->hash_func(p) ^ h->random_xor) % h->n_buckets;
+ return (unsigned) (h->hash_func(p, h->hash_key) % h->n_buckets);
+}
+
+static void get_hash_key(uint8_t hash_key[HASH_KEY_SIZE], bool reuse_is_ok) {
+ static uint8_t current[HASH_KEY_SIZE];
+ static bool current_initialized = false;
+
+ /* Returns a hash function key to use. In order to keep things
+ * fast we will not generate a new key each time we allocate a
+ * new hash table. Instead, we'll just reuse the most recently
+ * generated one, except if we never generated one or when we
+ * are rehashing an entire hash table because we reached a
+ * fill level */
+
+ if (!current_initialized || !reuse_is_ok) {
+ random_bytes(current, sizeof(current));
+ current_initialized = true;
+ }
+
+ memcpy(hash_key, current, sizeof(current));
}
Hashmap *hashmap_new(hash_func_t hash_func, compare_func_t compare_func) {
@@ -214,21 +220,7 @@ Hashmap *hashmap_new(hash_func_t hash_func, compare_func_t compare_func) {
h->from_pool = b;
- /* Let's randomize our hash functions a bit so that they are
- * harder to guess for clients. For this, start out by cheaply
- * using some bits the kernel passed into the process using
- * the auxiliary vector. If the hashmap grows later on we will
- * rehash everything using a new random XOR mask from
- * /dev/random. */
-#ifdef HAVE_SYS_AUXV_H
- {
- void *auxv;
- auxv = (void*) getauxval(AT_RANDOM);
- h->random_xor = auxv ? *(unsigned*) auxv : random_u();
- }
-#else
- h->random_xor = random_u();
-#endif
+ get_hash_key(h->hash_key, true);
return h;
}
@@ -407,7 +399,8 @@ static struct hashmap_entry *hash_scan(Hashmap *h, unsigned hash, const void *ke
static bool resize_buckets(Hashmap *h) {
struct hashmap_entry **n, *i;
- unsigned m, nxor;
+ unsigned m;
+ uint8_t nkey[HASH_KEY_SIZE];
assert(h);
@@ -422,15 +415,15 @@ static bool resize_buckets(Hashmap *h) {
if (!n)
return false;
- /* Let's use a different randomized xor value for the
+ /* Let's use a different randomized hash key for the
* extension, so that people cannot guess what we are using
* here forever */
- nxor = random_u();
+ get_hash_key(nkey, false);
for (i = h->iterate_list_head; i; i = i->iterate_next) {
- unsigned hash, x;
+ unsigned long old_bucket, new_bucket;
- hash = h->hash_func(i->key);
+ old_bucket = h->hash_func(i->key, h->hash_key) % h->n_buckets;
/* First, drop from old bucket table */
if (i->bucket_next)
@@ -439,16 +432,16 @@ static bool resize_buckets(Hashmap *h) {
if (i->bucket_previous)
i->bucket_previous->bucket_next = i->bucket_next;
else
- h->buckets[(hash ^ h->random_xor) % h->n_buckets] = i->bucket_next;
+ h->buckets[old_bucket] = i->bucket_next;
/* Then, add to new backet table */
- x = (hash ^ nxor) % m;
+ new_bucket = h->hash_func(i->key, nkey) % m;
- i->bucket_next = n[x];
+ i->bucket_next = n[new_bucket];
i->bucket_previous = NULL;
- if (n[x])
- n[x]->bucket_previous = i;
- n[x] = i;
+ if (n[new_bucket])
+ n[new_bucket]->bucket_previous = i;
+ n[new_bucket] = i;
}
if (h->buckets != (struct hashmap_entry**) ((uint8_t*) h + ALIGN(sizeof(Hashmap))))
@@ -456,7 +449,8 @@ static bool resize_buckets(Hashmap *h) {
h->buckets = n;
h->n_buckets = m;
- h->random_xor = nxor;
+
+ memcpy(h->hash_key, nkey, HASH_KEY_SIZE);
return true;
}
diff --git a/src/shared/hashmap.h b/src/shared/hashmap.h
index b912af8d8f..154f68eaf0 100644
--- a/src/shared/hashmap.h
+++ b/src/shared/hashmap.h
@@ -31,6 +31,8 @@
* for all read operations. That way it is not necessary to
* instantiate an object for each Hashmap use. */
+#define HASH_KEY_SIZE 16
+
typedef struct Hashmap Hashmap;
typedef struct _IteratorStruct _IteratorStruct;
typedef _IteratorStruct* Iterator;
@@ -38,19 +40,19 @@ typedef _IteratorStruct* Iterator;
#define ITERATOR_FIRST ((Iterator) 0)
#define ITERATOR_LAST ((Iterator) -1)
-typedef unsigned (*hash_func_t)(const void *p);
+typedef unsigned long (*hash_func_t)(const void *p, const uint8_t hash_key[HASH_KEY_SIZE]);
typedef int (*compare_func_t)(const void *a, const void *b);
-unsigned string_hash_func(const void *p) _pure_;
+unsigned long string_hash_func(const void *p, const uint8_t hash_key[HASH_KEY_SIZE]) _pure_;
int string_compare_func(const void *a, const void *b) _pure_;
/* This will compare the passed pointers directly, and will not
* dereference them. This is hence not useful for strings or
* suchlike. */
-unsigned trivial_hash_func(const void *p) _const_;
+unsigned long trivial_hash_func(const void *p, const uint8_t hash_key[HASH_KEY_SIZE]) _pure_;
int trivial_compare_func(const void *a, const void *b) _const_;
-unsigned uint64_hash_func(const void *p) _pure_;
+unsigned long uint64_hash_func(const void *p, const uint8_t hash_key[HASH_KEY_SIZE]) _pure_;
int uint64_compare_func(const void *a, const void *b) _pure_;
Hashmap *hashmap_new(hash_func_t hash_func, compare_func_t compare_func);
diff --git a/src/shared/siphash24.c b/src/shared/siphash24.c
new file mode 100644
index 0000000000..f68bd283a1
--- /dev/null
+++ b/src/shared/siphash24.c
@@ -0,0 +1,135 @@
+/*
+ SipHash reference C implementation
+
+ Written in 2012 by
+ Jean-Philippe Aumasson <jeanphilippe.aumasson@gmail.com>
+ Daniel J. Bernstein <djb@cr.yp.to>
+
+ To the extent possible under law, the author(s) have dedicated all copyright
+ and related and neighboring rights to this software to the public domain
+ worldwide. This software is distributed without any warranty.
+
+ You should have received a copy of the CC0 Public Domain Dedication along with
+ this software. If not, see <http://creativecommons.org/publicdomain/zero/1.0/>.
+
+ (Minimal changes made by Lennart Poettering, to make clean for inclusion in systemd)
+*/
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "siphash24.h"
+
+typedef uint64_t u64;
+typedef uint32_t u32;
+typedef uint8_t u8;
+
+#define ROTL(x,b) (u64)( ((x) << (b)) | ( (x) >> (64 - (b))) )
+
+#define U32TO8_LE(p, v) \
+ (p)[0] = (u8)((v) ); (p)[1] = (u8)((v) >> 8); \
+ (p)[2] = (u8)((v) >> 16); (p)[3] = (u8)((v) >> 24);
+
+#define U64TO8_LE(p, v) \
+ U32TO8_LE((p), (u32)((v) )); \
+ U32TO8_LE((p) + 4, (u32)((v) >> 32));
+
+#define U8TO64_LE(p) \
+ (((u64)((p)[0]) ) | \
+ ((u64)((p)[1]) << 8) | \
+ ((u64)((p)[2]) << 16) | \
+ ((u64)((p)[3]) << 24) | \
+ ((u64)((p)[4]) << 32) | \
+ ((u64)((p)[5]) << 40) | \
+ ((u64)((p)[6]) << 48) | \
+ ((u64)((p)[7]) << 56))
+
+#define SIPROUND \
+ do { \
+ v0 += v1; v1=ROTL(v1,13); v1 ^= v0; v0=ROTL(v0,32); \
+ v2 += v3; v3=ROTL(v3,16); v3 ^= v2; \
+ v0 += v3; v3=ROTL(v3,21); v3 ^= v0; \
+ v2 += v1; v1=ROTL(v1,17); v1 ^= v2; v2=ROTL(v2,32); \
+ } while(0)
+
+/* SipHash-2-4 */
+void siphash24(uint8_t out[8], const void *_in, size_t inlen, const uint8_t k[16])
+{
+ /* "somepseudorandomlygeneratedbytes" */
+ u64 v0 = 0x736f6d6570736575ULL;
+ u64 v1 = 0x646f72616e646f6dULL;
+ u64 v2 = 0x6c7967656e657261ULL;
+ u64 v3 = 0x7465646279746573ULL;
+ u64 b;
+ u64 k0 = U8TO64_LE( k );
+ u64 k1 = U8TO64_LE( k + 8 );
+ u64 m;
+ const u8 *in = _in;
+ const u8 *end = in + inlen - ( inlen % sizeof( u64 ) );
+ const int left = inlen & 7;
+ b = ( ( u64 )inlen ) << 56;
+ v3 ^= k1;
+ v2 ^= k0;
+ v1 ^= k1;
+ v0 ^= k0;
+
+ for ( ; in != end; in += 8 )
+ {
+ m = U8TO64_LE( in );
+#ifdef DEBUG
+ printf( "(%3d) v0 %08x %08x\n", ( int )inlen, ( u32 )( v0 >> 32 ), ( u32 )v0 );
+ printf( "(%3d) v1 %08x %08x\n", ( int )inlen, ( u32 )( v1 >> 32 ), ( u32 )v1 );
+ printf( "(%3d) v2 %08x %08x\n", ( int )inlen, ( u32 )( v2 >> 32 ), ( u32 )v2 );
+ printf( "(%3d) v3 %08x %08x\n", ( int )inlen, ( u32 )( v3 >> 32 ), ( u32 )v3 );
+ printf( "(%3d) compress %08x %08x\n", ( int )inlen, ( u32 )( m >> 32 ), ( u32 )m );
+#endif
+ v3 ^= m;
+ SIPROUND;
+ SIPROUND;
+ v0 ^= m;
+ }
+
+ switch( left )
+ {
+ case 7: b |= ( ( u64 )in[ 6] ) << 48;
+
+ case 6: b |= ( ( u64 )in[ 5] ) << 40;
+
+ case 5: b |= ( ( u64 )in[ 4] ) << 32;
+
+ case 4: b |= ( ( u64 )in[ 3] ) << 24;
+
+ case 3: b |= ( ( u64 )in[ 2] ) << 16;
+
+ case 2: b |= ( ( u64 )in[ 1] ) << 8;
+
+ case 1: b |= ( ( u64 )in[ 0] ); break;
+
+ case 0: break;
+ }
+
+#ifdef DEBUG
+ printf( "(%3d) v0 %08x %08x\n", ( int )inlen, ( u32 )( v0 >> 32 ), ( u32 )v0 );
+ printf( "(%3d) v1 %08x %08x\n", ( int )inlen, ( u32 )( v1 >> 32 ), ( u32 )v1 );
+ printf( "(%3d) v2 %08x %08x\n", ( int )inlen, ( u32 )( v2 >> 32 ), ( u32 )v2 );
+ printf( "(%3d) v3 %08x %08x\n", ( int )inlen, ( u32 )( v3 >> 32 ), ( u32 )v3 );
+ printf( "(%3d) padding %08x %08x\n", ( int )inlen, ( u32 )( b >> 32 ), ( u32 )b );
+#endif
+ v3 ^= b;
+ SIPROUND;
+ SIPROUND;
+ v0 ^= b;
+#ifdef DEBUG
+ printf( "(%3d) v0 %08x %08x\n", ( int )inlen, ( u32 )( v0 >> 32 ), ( u32 )v0 );
+ printf( "(%3d) v1 %08x %08x\n", ( int )inlen, ( u32 )( v1 >> 32 ), ( u32 )v1 );
+ printf( "(%3d) v2 %08x %08x\n", ( int )inlen, ( u32 )( v2 >> 32 ), ( u32 )v2 );
+ printf( "(%3d) v3 %08x %08x\n", ( int )inlen, ( u32 )( v3 >> 32 ), ( u32 )v3 );
+#endif
+ v2 ^= 0xff;
+ SIPROUND;
+ SIPROUND;
+ SIPROUND;
+ SIPROUND;
+ b = v0 ^ v1 ^ v2 ^ v3;
+ U64TO8_LE( out, b );
+}
diff --git a/src/shared/siphash24.h b/src/shared/siphash24.h
new file mode 100644
index 0000000000..62e1168a79
--- /dev/null
+++ b/src/shared/siphash24.h
@@ -0,0 +1,6 @@
+#pragma once
+
+#include <inttypes.h>
+#include <sys/types.h>
+
+void siphash24(uint8_t out[8], const void *in, size_t inlen, const uint8_t k[16]);
diff --git a/src/shared/util.c b/src/shared/util.c
index 481c17245d..5c9d0bb730 100644
--- a/src/shared/util.c
+++ b/src/shared/util.c
@@ -61,6 +61,10 @@
#include <libgen.h>
#undef basename
+#ifdef HAVE_SYS_AUXV_H
+#include <sys/auxv.h>
+#endif
+
#include "macro.h"
#include "util.h"
#include "ioprio.h"
@@ -2345,42 +2349,48 @@ char* dirname_malloc(const char *path) {
return dir;
}
-unsigned long long random_ull(void) {
+void random_bytes(void *p, size_t n) {
+ static bool srand_called = false;
_cleanup_close_ int fd;
- uint64_t ull;
- ssize_t r;
+ ssize_t k;
+ uint8_t *q;
fd = open("/dev/urandom", O_RDONLY|O_CLOEXEC|O_NOCTTY);
if (fd < 0)
goto fallback;
- r = loop_read(fd, &ull, sizeof(ull), true);
- if (r != sizeof(ull))
+ k = loop_read(fd, p, n, true);
+ if (k < 0 || (size_t) k != n)
goto fallback;
- return ull;
+ return;
fallback:
- return random() * RAND_MAX + random();
-}
-unsigned random_u(void) {
- _cleanup_close_ int fd;
- unsigned u;
- ssize_t r;
+ if (!srand_called) {
- fd = open("/dev/urandom", O_RDONLY|O_CLOEXEC|O_NOCTTY);
- if (fd < 0)
- goto fallback;
+#ifdef HAVE_SYS_AUXV_H
+ /* The kernel provides us with a bit of entropy in
+ * auxv, so let's try to make use of that to seed the
+ * pseudo-random generator. It's better than
+ * nothing... */
- r = loop_read(fd, &u, sizeof(u), true);
- if (r != sizeof(u))
- goto fallback;
+ void *auxv;
- return u;
+ auxv = (void*) getauxval(AT_RANDOM);
+ if (auxv)
+ srand(*(unsigned*) auxv);
+ else
+#endif
+ srand(time(NULL) + gettid());
-fallback:
- return random() * RAND_MAX + random();
+ srand_called = true;
+ }
+
+ /* If some idiot made /dev/urandom unavailable to us, he'll
+ * get a PRNG instead. */
+ for (q = p; q < (uint8_t*) p + n; q ++)
+ *q = rand();
}
void rename_process(const char name[8]) {
@@ -4137,7 +4147,7 @@ int symlink_atomic(const char *from, const char *to) {
_cleanup_free_ char *t;
const char *fn;
size_t k;
- unsigned long long ull;
+ uint64_t u;
unsigned i;
int r;
@@ -4154,10 +4164,10 @@ int symlink_atomic(const char *from, const char *to) {
t[k] = '.';
x = stpcpy(t+k+1, fn);
- ull = random_ull();
+ u = random_u64();
for (i = 0; i < 16; i++) {
- *(x++) = hexchar(ull & 0xF);
- ull >>= 4;
+ *(x++) = hexchar(u & 0xF);
+ u >>= 4;
}
*x = 0;
diff --git a/src/shared/util.h b/src/shared/util.h
index 488ce3ba6d..338d79c7ac 100644
--- a/src/shared/util.h
+++ b/src/shared/util.h
@@ -249,8 +249,19 @@ int make_stdio(int fd);
int make_null_stdio(void);
int make_console_stdio(void);
-unsigned long long random_ull(void);
-unsigned random_u(void);
+void random_bytes(void *p, size_t n);
+
+static inline uint64_t random_u64(void) {
+ uint64_t u;
+ random_bytes(&u, sizeof(u));
+ return u;
+}
+
+static inline uint32_t random_u32(void) {
+ uint32_t u;
+ random_bytes(&u, sizeof(u));
+ return u;
+}
/* For basic lookup tables with strictly enumerated entries */
#define __DEFINE_STRING_TABLE_LOOKUP(name,type,scope) \
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-08-04 20:28:57 +0000