diff --git a/programs/README.md b/programs/README.md index ca9056ea..afbebaa1 100644 --- a/programs/README.md +++ b/programs/README.md @@ -172,6 +172,11 @@ Benchmark arguments : --priority=rt : set process priority to real-time ``` +#### Restricted usage of Environment Variables +Using environment variables to set compression/decompression parameters has security implications. Therefore, +we intentionally restrict its usage. Currently, only `ZSTD_CLEVEL` is supported for setting compression level. +If the value of `ZSTD_CLEVEL` is not a valid integer, it will be ignored with a warning message. +Note that command line options will override corresponding environment variable settings. #### Long distance matching mode The long distance matching mode, enabled with `--long`, is designed to improve diff --git a/programs/zstdcli.c b/programs/zstdcli.c index e69661d5..64dad110 100644 --- a/programs/zstdcli.c +++ b/programs/zstdcli.c @@ -28,6 +28,7 @@ #include "platform.h" /* IS_CONSOLE, PLATFORM_POSIX_VERSION */ #include "util.h" /* UTIL_HAS_CREATEFILELIST, UTIL_createFileList */ #include /* fprintf(), stdin, stdout, stderr */ +#include /* getenv */ #include /* strcmp, strlen */ #include /* errno */ #include "fileio.h" /* stdinmark, stdoutmark, ZSTD_EXTENSION */ @@ -233,32 +234,44 @@ static void errorOut(const char* msg) DISPLAY("%s \n", msg); exit(1); } -/*! readU32FromChar() : - * @return : unsigned integer value read from input in `char` format. +/*! readU32FromCharChecked() : + * @return 0 if success, and store the result in *value. * allows and interprets K, KB, KiB, M, MB and MiB suffix. * Will also modify `*stringPtr`, advancing it to position where it stopped reading. - * Note : function will exit() program if digit sequence overflows */ -static unsigned readU32FromChar(const char** stringPtr) + * @return 1 if an overflow error occurs */ +static int readU32FromCharChecked(const char** stringPtr, unsigned* value) { - const char errorMsg[] = "error: numeric value too large"; + static unsigned const max = (((unsigned)(-1)) / 10) - 1; unsigned result = 0; while ((**stringPtr >='0') && (**stringPtr <='9')) { - unsigned const max = (((unsigned)(-1)) / 10) - 1; - if (result > max) errorOut(errorMsg); + if (result > max) return 1; // overflow error result *= 10, result += **stringPtr - '0', (*stringPtr)++ ; } if ((**stringPtr=='K') || (**stringPtr=='M')) { unsigned const maxK = ((unsigned)(-1)) >> 10; - if (result > maxK) errorOut(errorMsg); + if (result > maxK) return 1; // overflow error result <<= 10; if (**stringPtr=='M') { - if (result > maxK) errorOut(errorMsg); + if (result > maxK) return 1; // overflow error result <<= 10; } (*stringPtr)++; /* skip `K` or `M` */ if (**stringPtr=='i') (*stringPtr)++; if (**stringPtr=='B') (*stringPtr)++; } + *value = result; + return 0; +} + +/*! readU32FromChar() : + * @return : unsigned integer value read from input in `char` format. + * allows and interprets K, KB, KiB, M, MB and MiB suffix. + * Will also modify `*stringPtr`, advancing it to position where it stopped reading. + * Note : function will exit() program if digit sequence overflows */ +static unsigned readU32FromChar(const char** stringPtr) { + static const char errorMsg[] = "error: numeric value too large"; + unsigned result; + if (readU32FromCharChecked(stringPtr, &result)) { errorOut(errorMsg); } return result; } @@ -452,6 +465,38 @@ static void printVersion(void) #endif } +/* Environment variables for parameter setting */ +#define ENV_CLEVEL "ZSTD_CLEVEL" + +/* functions that pick up environment variables */ +static int init_cLevel(void) { + const char* const env = getenv(ENV_CLEVEL); + if (env) { + const char *ptr = env; + int sign = 1; + if (*ptr == '-') { + sign = -1; + ptr++; + } else if (*ptr == '+') { + ptr++; + } + + if ((*ptr>='0') && (*ptr<='9')) { + unsigned absLevel; + if (readU32FromCharChecked(&ptr, &absLevel)) { + DISPLAYLEVEL(2, "Ignore environment variable setting %s=%s: numeric value too large\n", ENV_CLEVEL, env); + return ZSTDCLI_CLEVEL_DEFAULT; + } else if (*ptr == 0) { + return sign * absLevel; + } + } + + DISPLAYLEVEL(2, "Ignore environment variable setting %s=%s: not a valid integer value\n", ENV_CLEVEL, env); + } + + return ZSTDCLI_CLEVEL_DEFAULT; +} + typedef enum { zom_compress, zom_decompress, zom_test, zom_bench, zom_train, zom_list } zstd_operation_mode; #define CLEAN_RETURN(i) { operationResult = (i); goto _end; } @@ -493,7 +538,7 @@ int main(int argCount, const char* argv[]) size_t blockSize = 0; zstd_operation_mode operation = zom_compress; ZSTD_compressionParameters compressionParams; - int cLevel = ZSTDCLI_CLEVEL_DEFAULT; + int cLevel; int cLevelLast = -1000000000; unsigned recursive = 0; unsigned memLimit = 0; @@ -528,6 +573,7 @@ int main(int argCount, const char* argv[]) if (filenameTable==NULL) { DISPLAY("zstd: %s \n", strerror(errno)); exit(1); } filenameTable[0] = stdinmark; g_displayOut = stderr; + cLevel = init_cLevel(); programName = lastNameFromPath(programName); #ifdef ZSTD_MULTITHREAD nbWorkers = 1; diff --git a/tests/playTests.sh b/tests/playTests.sh index b861391e..e77f10e5 100755 --- a/tests/playTests.sh +++ b/tests/playTests.sh @@ -122,6 +122,18 @@ $ZSTD --fast=5000000000 -f tmp && die "too large numeric value : must fail" $ZSTD -c --fast=0 tmp > $INTOVOID && die "--fast must not accept value 0" $ECHO "test : too large numeric argument" $ZSTD --fast=9999999999 -f tmp && die "should have refused numeric value" +$ECHO "test : set compression level with environment variable ZSTD_CLEVEL" +ZSTD_CLEVEL=12 $ZSTD -f tmp # positive compression level +ZSTD_CLEVEL=-12 $ZSTD -f tmp # negative compression level +ZSTD_CLEVEL=+12 $ZSTD -f tmp # valid: verbose '+' sign +ZSTD_CLEVEL= $ZSTD -f tmp # empty env var, warn and revert to default setting +ZSTD_CLEVEL=- $ZSTD -f tmp # malformed env var, warn and revert to default setting +ZSTD_CLEVEL=a $ZSTD -f tmp # malformed env var, warn and revert to default setting +ZSTD_CLEVEL=+a $ZSTD -f tmp # malformed env var, warn and revert to default setting +ZSTD_CLEVEL=3a7 $ZSTD -f tmp # malformed env var, warn and revert to default setting +ZSTD_CLEVEL=50000000000 $ZSTD -f tmp # numeric value too large, warn and revert to default setting +$ECHO "test : override ZSTD_CLEVEL with command line option" +ZSTD_CLEVEL=12 $ZSTD --fast=3 -f tmp # overridden by command line option $ECHO "test : compress to stdout" $ZSTD tmp -c > tmpCompressed $ZSTD tmp --stdout > tmpCompressed # long command format