# git rev-parse -q --verify a680b1832ced3b5fa7c93484248fd221ea0d614b^{commit} a680b1832ced3b5fa7c93484248fd221ea0d614b already have revision, skipping fetch # git checkout -q -f -B kisskb a680b1832ced3b5fa7c93484248fd221ea0d614b # git clean -qxdf # < git log -1 # commit a680b1832ced3b5fa7c93484248fd221ea0d614b # Author: Brian Masney # Date: Thu Mar 10 18:24:59 2022 -0500 # # crypto: qcom-rng - ensure buffer for generate is completely filled # # The generate function in struct rng_alg expects that the destination # buffer is completely filled if the function returns 0. qcom_rng_read() # can run into a situation where the buffer is partially filled with # randomness and the remaining part of the buffer is zeroed since # qcom_rng_generate() doesn't check the return value. This issue can # be reproduced by running the following from libkcapi: # # kcapi-rng -b 9000000 > OUTFILE # # The generated OUTFILE will have three huge sections that contain all # zeros, and this is caused by the code where the test # 'val & PRNG_STATUS_DATA_AVAIL' fails. # # Let's fix this issue by ensuring that qcom_rng_read() always returns # with a full buffer if the function returns success. Let's also have # qcom_rng_generate() return the correct value. # # Here's some statistics from the ent project # (https://www.fourmilab.ch/random/) that shows information about the # quality of the generated numbers: # # $ ent -c qcom-random-before # Value Char Occurrences Fraction # 0 606748 0.067416 # 1 33104 0.003678 # 2 33001 0.003667 # ... # 253 � 32883 0.003654 # 254 � 33035 0.003671 # 255 � 33239 0.003693 # # Total: 9000000 1.000000 # # Entropy = 7.811590 bits per byte. # # Optimum compression would reduce the size # of this 9000000 byte file by 2 percent. # # Chi square distribution for 9000000 samples is 9329962.81, and # randomly would exceed this value less than 0.01 percent of the # times. # # Arithmetic mean value of data bytes is 119.3731 (127.5 = random). # Monte Carlo value for Pi is 3.197293333 (error 1.77 percent). # Serial correlation coefficient is 0.159130 (totally uncorrelated = # 0.0). # # Without this patch, the results of the chi-square test is 0.01%, and # the numbers are certainly not random according to ent's project page. # The results improve with this patch: # # $ ent -c qcom-random-after # Value Char Occurrences Fraction # 0 35432 0.003937 # 1 35127 0.003903 # 2 35424 0.003936 # ... # 253 � 35201 0.003911 # 254 � 34835 0.003871 # 255 � 35368 0.003930 # # Total: 9000000 1.000000 # # Entropy = 7.999979 bits per byte. # # Optimum compression would reduce the size # of this 9000000 byte file by 0 percent. # # Chi square distribution for 9000000 samples is 258.77, and randomly # would exceed this value 42.24 percent of the times. # # Arithmetic mean value of data bytes is 127.5006 (127.5 = random). # Monte Carlo value for Pi is 3.141277333 (error 0.01 percent). # Serial correlation coefficient is 0.000468 (totally uncorrelated = # 0.0). # # This change was tested on a Nexus 5 phone (msm8974 SoC). # # Signed-off-by: Brian Masney # Fixes: ceec5f5b5988 ("crypto: qcom-rng - Add Qcom prng driver") # Cc: stable@vger.kernel.org # 4.19+ # Reviewed-by: Bjorn Andersson # Reviewed-by: Andrew Halaney # Signed-off-by: Herbert Xu # < /opt/cross/kisskb/korg/gcc-11.1.0-nolibc/x86_64-linux/bin/x86_64-linux-gcc --version # < /opt/cross/kisskb/korg/gcc-11.1.0-nolibc/x86_64-linux/bin/x86_64-linux-ld --version # < git log --format=%s --max-count=1 a680b1832ced3b5fa7c93484248fd221ea0d614b # < make -s -j 8 ARCH=x86_64 O=/kisskb/build/crypto_x86_64-allnoconfig_x86_64-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.1.0-nolibc/x86_64-linux/bin/x86_64-linux- allnoconfig # < make -s -j 8 ARCH=x86_64 O=/kisskb/build/crypto_x86_64-allnoconfig_x86_64-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.1.0-nolibc/x86_64-linux/bin/x86_64-linux- help # make -s -j 8 ARCH=x86_64 O=/kisskb/build/crypto_x86_64-allnoconfig_x86_64-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.1.0-nolibc/x86_64-linux/bin/x86_64-linux- olddefconfig # make -s -j 8 ARCH=x86_64 O=/kisskb/build/crypto_x86_64-allnoconfig_x86_64-gcc11 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-11.1.0-nolibc/x86_64-linux/bin/x86_64-linux- Completed OK # rm -rf /kisskb/build/crypto_x86_64-allnoconfig_x86_64-gcc11 # Build took: 0:00:54.193297