mbedtls/library
Hanno Becker 27516979c1 Entropy: Fall through to /dev/random if getrandom() syscall unknown
This commit fixes issue #1212 related to platform-specific entropy
polling in an syscall-emulated environment.

Previously, the implementation of the entropy gathering function
`mbedtls_platform_entropy_poll()` for linux machines used the
following logic to determine how to obtain entropy from the kernel:

1. If the getrandom() system call identifier SYS_getrandom is present and
   the kernel version is 3.17 or higher, use syscall( SYS_getrandom, ... )
2. Otherwise, fall back to reading from /dev/random.

There are two issues with this:

1. Portability:
   When cross-compiling the code for a different
   architecture and running it through system call
   emulation in qemu, qemu reports the host kernel
   version through uname but, as of v.2.5.0,
   doesn't support emulating the getrandom() syscall.
   This leads to `mbedtls_platform_entropy_poll()`
   failing even though reading from /dev/random would
   have worked.

2. Style:
   Extracting the linux kernel version from
   the output of `uname` is slightly tedious.

This commit fixes both by implementing the suggestion in #1212:
- It removes the kernel-version detection through uname().
- Instead, it checks whether `syscall( SYS_getrandom, ... )`
  fails with errno set to ENOSYS indicating an unknown system call.
  If so, it falls through to trying to read from /dev/random.

Fixes #1212.
2018-10-18 12:12:04 +01:00
..
.gitignore Split libs with make + general make cleanups 2015-06-25 10:59:56 +02:00
aes.c Merge remote-tracking branch 'public/pr/1736' into development 2018-06-17 17:34:55 +01:00
aesni.c Warn if using a memory sanitizer on AESNI 2018-04-05 15:37:38 +02:00
arc4.c Rename mbedtls_zeroize to mbedtls_platform_zeroize 2018-04-17 10:00:21 -05:00
aria.c Use mbedtls_printf instead of printf 2018-08-13 13:49:52 +03:00
asn1parse.c Rename mbedtls_zeroize to mbedtls_platform_zeroize 2018-04-17 10:00:21 -05:00
asn1write.c Treat warnings as errors for IAR 2018-05-25 14:54:14 +01:00
base64.c Add comment to integer overflow fix in base64.c 2017-02-15 23:31:07 +02:00
bignum.c Merge remote-tracking branch 'upstream-restricted/pr/421' into development-proposed 2018-05-04 14:39:24 +01:00
blowfish.c Rename mbedtls_zeroize to mbedtls_platform_zeroize 2018-04-17 10:00:21 -05:00
camellia.c Rename mbedtls_zeroize to mbedtls_platform_zeroize 2018-04-17 10:00:21 -05:00
ccm.c enforce input and output of ccm selftest on stack 2018-07-30 11:29:26 +03:00
certs.c Undo API change from SHA1 deprecation 2017-07-27 21:44:33 +01:00
chacha20.c Fix usage of inline with for some compilers 2018-06-07 11:54:17 +02:00
chachapoly.c Fix a few typos 2018-06-18 10:30:30 +02:00
cipher.c Move definition of MBEDTLS_CIPHER_MODE_STREAM 2018-07-01 10:20:43 +03:00
cipher_wrap.c Define specific mode for ChachaPoly 2018-06-19 11:32:48 +02:00
cmac.c Merge remote-tracking branch 'public/pr/1390' into development 2018-06-27 10:51:47 +01:00
CMakeLists.txt Update library version number to 2.13.1 2018-09-06 19:10:26 +01:00
ctr_drbg.c Rename mbedtls_zeroize to mbedtls_platform_zeroize 2018-04-17 10:00:21 -05:00
debug.c Fix compilation error with Mingw32 2017-09-06 17:51:14 +03:00
des.c Rename mbedtls_zeroize to mbedtls_platform_zeroize 2018-04-17 10:00:21 -05:00
dhm.c Rename mbedtls_zeroize to mbedtls_platform_zeroize 2018-04-17 10:00:21 -05:00
ecdh.c Address PR cpomments reviews 2017-10-10 19:04:27 +03:00
ecdsa.c Clarify the use of MBEDTLS_ERR_PK_SIG_LEN_MISMATCH 2018-03-30 18:43:16 +02:00
ecjpake.c Fix minor code style issues 2018-05-15 09:21:57 +01:00
ecp.c Remove redundant else statement 2018-08-20 10:39:27 +03:00
ecp_curves.c Merge branch 'pr_348' into development-proposed 2018-04-04 09:18:27 +02:00
entropy.c Rename mbedtls_zeroize to mbedtls_platform_zeroize 2018-04-17 10:00:21 -05:00
entropy_poll.c Entropy: Fall through to /dev/random if getrandom() syscall unknown 2018-10-18 12:12:04 +01:00
error.c Update error codes 2018-08-17 16:52:08 +01:00
gcm.c Rename mbedtls_zeroize to mbedtls_platform_zeroize 2018-04-17 10:00:21 -05:00
havege.c Rename mbedtls_zeroize to mbedtls_platform_zeroize 2018-04-17 10:00:21 -05:00
hkdf.c Fix issue if salt = NULL and salt_len !=0 in mbedtls_hkdf_extract() 2018-07-23 10:34:47 -07:00
hmac_drbg.c Rename mbedtls_zeroize to mbedtls_platform_zeroize 2018-04-17 10:00:21 -05:00
Makefile Update library version number to 2.13.0 2018-08-31 15:59:10 +01:00
md.c Rename mbedtls_zeroize to mbedtls_platform_zeroize 2018-04-17 10:00:21 -05:00
md2.c Rename mbedtls_zeroize to mbedtls_platform_zeroize 2018-04-17 10:00:21 -05:00
md4.c Rename mbedtls_zeroize to mbedtls_platform_zeroize 2018-04-17 10:00:21 -05:00
md5.c Fix Lucky 13 cache attack on MD/SHA padding 2018-07-05 10:47:00 +02:00
md_wrap.c New MD API: rename functions from _ext to _ret 2018-01-22 11:54:42 +01:00
memory_buffer_alloc.c Fix braces in mbedtls_memory_buffer_alloc_status() 2018-06-12 16:56:04 +01:00
net_sockets.c Merge remote-tracking branch 'public/pr/1198' into development 2018-07-24 17:20:17 +01:00
nist_kw.c Add selftests 2018-07-24 16:43:20 +01:00
oid.c pkcs5v2: add support for additional hmacSHA algorithms 2018-02-08 17:18:15 +08:00
padlock.c Change main license to Apache 2.0 2015-09-04 14:21:07 +02:00
pem.c Rename mbedtls_zeroize to mbedtls_platform_zeroize 2018-04-17 10:00:21 -05:00
pk.c Rename mbedtls_zeroize to mbedtls_platform_zeroize 2018-04-17 10:00:21 -05:00
pk_wrap.c Rename mbedtls_zeroize to mbedtls_platform_zeroize 2018-04-17 10:00:21 -05:00
pkcs5.c Treat warnings as errors for IAR 2018-05-25 14:54:14 +01:00
pkcs11.c Change main license to Apache 2.0 2015-09-04 14:21:07 +02:00
pkcs12.c Rename mbedtls_zeroize to mbedtls_platform_zeroize 2018-04-17 10:00:21 -05:00
pkparse.c Remove unnecessary mark as unused #1098 2018-07-11 15:16:53 +02:00
pkwrite.c Adapt PK test suite to use new interface 2017-08-23 16:17:27 +01:00
platform.c Convert mbedtls_free and mbedtls_calloc into functions 2018-06-13 09:17:59 +01:00
platform_util.c Don't declare and define gmtime()-mutex on Windows platforms 2018-09-06 12:09:56 +01:00
poly1305.c Fix usage of inline with for some compilers 2018-06-07 11:54:17 +02:00
ripemd160.c Rename mbedtls_zeroize to mbedtls_platform_zeroize 2018-04-17 10:00:21 -05:00
rsa.c Merge remote-tracking branch 'upstream-restricted/pr/421' into development-proposed 2018-05-04 14:39:24 +01:00
rsa_internal.c Add explicit type cast to avoid truncation warning 2018-01-03 09:27:40 +00:00
sha1.c Fix Lucky 13 cache attack on MD/SHA padding 2018-07-05 10:47:00 +02:00
sha256.c Fix Lucky 13 cache attack on MD/SHA padding 2018-07-05 10:47:00 +02:00
sha512.c Fix Lucky 13 cache attack on MD/SHA padding 2018-07-05 10:47:00 +02:00
ssl_cache.c Address PR review comments 2017-10-29 17:53:52 +02:00
ssl_ciphersuites.c Merge remote-tracking branch 'upstream-public/pr/1378' into development 2018-08-10 10:59:53 +01:00
ssl_cli.c Merge remote-tracking branch 'public/pr/1988' into development 2018-08-30 00:57:28 +01:00
ssl_cookie.c Rename mbedtls_zeroize to mbedtls_platform_zeroize 2018-04-17 10:00:21 -05:00
ssl_srv.c Style: Add numerous comments indicating condition guarded by #endif 2018-08-28 10:13:29 +01:00
ssl_ticket.c Fix bug in SSL ticket implementation removing keys of age < 1s 2018-08-21 17:48:52 +01:00
ssl_tls.c Merge branch 'development' into development 2018-08-30 01:11:35 +01:00
threading.c Don't declare and define gmtime()-mutex on Windows platforms 2018-09-06 12:09:56 +01:00
timing.c library: Port to Haiku. 2018-04-11 20:27:32 -04:00
version.c Fix missing void argument declarations #678 2016-11-04 23:05:56 +01:00
version_features.c Key wrapping API definition 2018-07-24 16:43:20 +01:00
x509.c Rename mbedtls_platform_gmtime() to mbedtls_platform_gmtime_r() 2018-09-05 15:06:19 +01:00
x509_create.c Fix other occurrences of same bounds check issue 2015-10-21 12:50:45 +02:00
x509_crl.c Rename mbedtls_zeroize to mbedtls_platform_zeroize 2018-04-17 10:00:21 -05:00
x509_crt.c Merge remote-tracking branch 'restricted/pr/470' into development-restricted 2018-08-28 15:26:11 +01:00
x509_csr.c Merge remote-tracking branch 'public/pr/1621' into development 2018-06-28 12:09:15 +01:00
x509write_crt.c Rename mbedtls_zeroize to mbedtls_platform_zeroize 2018-04-17 10:00:21 -05:00
x509write_csr.c Rename mbedtls_zeroize to mbedtls_platform_zeroize 2018-04-17 10:00:21 -05:00
xtea.c Rename mbedtls_zeroize to mbedtls_platform_zeroize 2018-04-17 10:00:21 -05:00