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Fix #431: [bug bounty] readpass_file() silently truncates the passphrase at a carriage return #433

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Fix #431: [bug bounty] readpass_file() silently truncates the passphrase at a carriage return #433

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25 changes: 23 additions & 2 deletions libcperciva/util/readpass_file.c
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Original file line number Diff line number Diff line change
Expand Up @@ -52,8 +52,29 @@ readpass_file(char ** passwd, const char * filename)
goto err1;
}

/* Truncate at any newline character. */
passbuf[strcspn(passbuf, "\r\n")] = '\0';
/*
* Strip a trailing "\n" or a trailing "\r\n" explicitly, then reject the
* file if any "\r" or "\n" remains. This matches the contract in
* readpass.h: only a single trailing newline ("\n") or CRLF ("\r\n") is
* permitted at the end of the file; any other occurrences of CR or LF are
* an error.
*/
{
size_t len = strlen(passbuf);

/* Strip trailing '\n', and an optional preceding '\r'. */
if (len > 0 && passbuf[len - 1] == '\n') {
passbuf[--len] = '\0';
if (len > 0 && passbuf[len - 1] == '\r')
passbuf[--len] = '\0';
}

/* If any CR or LF remains, the file contains embedded newlines. */
if (strchr(passbuf, '\r') != NULL || strchr(passbuf, '\n') != NULL) {
warn0("Invalid passphrase file: %s", filename);
goto err1;
}
}

/* Copy the password out. */
if ((*passwd = strdup(passbuf)) == NULL) {
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22 changes: 11 additions & 11 deletions tests/08-passphrase-file.sh
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Original file line number Diff line number Diff line change
Expand Up @@ -13,12 +13,12 @@ decrypted_no_file_log="${s_basename}-decrypt-no-file.log"

scenario_cmd() {
# Create the passphrase file.
echo "${password}" > "${passphrase_file}"
printf "%s\n" "${password}" > "${passphrase_file}"

# Decrypt a reference file using --passphrase file:FILENAME.
setup_check "scrypt dec file"
${c_valgrind_cmd} "${bindir}/scrypt" \
dec --passphrase file:"${passphrase_file}" \
${c_valgrind_cmd} "${bindir}/scrypt" \
dec --passphrase file:"${passphrase_file}" \
"${encrypted_reference_file}" "${decrypted_reference_file}"
echo $? > "${c_exitfile}"

Expand All @@ -30,15 +30,15 @@ scenario_cmd() {
# Attempt to decrypt the reference file with a non-existent file.
# We want this command to fail with 1.
setup_check "scrypt dec file none"
${c_valgrind_cmd} "${bindir}/scrypt" \
dec --passphrase file:THIS_FILE_DOES_NOT_EXIST \
"${encrypted_reference_file}" "${decrypted_reference_file}" \
${c_valgrind_cmd} "${bindir}/scrypt" \
dec --passphrase file:THIS_FILE_DOES_NOT_EXIST \
"${encrypted_reference_file}" "${decrypted_reference_file}" \
2> "${decrypted_no_file_log}"
expected_exitcode 1 $? > "${c_exitfile}"

# We should have received an error message.
setup_check "scrypt dec file none error"
grep -q "scrypt: fopen(THIS_FILE_DOES_NOT_EXIST)" \
grep -q "scrypt: fopen(THIS_FILE_DOES_NOT_EXIST)" \
"${decrypted_no_file_log}"
echo "$?" > "${c_exitfile}"

Expand All @@ -50,10 +50,10 @@ scenario_cmd() {
# Attempt to decrypt the reference file with an incorrect passphrase.
# We want this command to fail with 1.
setup_check "scrypt dec file bad"
echo "bad-pass" > "${bad_passphrase_file}"
${c_valgrind_cmd} "${bindir}/scrypt" \
dec --passphrase file:"${bad_passphrase_file}" \
"${encrypted_reference_file}" "${decrypted_reference_file}" \
printf "bad-pass\n" > "${bad_passphrase_file}"
${c_valgrind_cmd} "${bindir}/scrypt" \
dec --passphrase file:"${bad_passphrase_file}" \
"${encrypted_reference_file}" "${decrypted_reference_file}" \
2> "${decrypted_badpass_log}"
expected_exitcode 1 $? > "${c_exitfile}"

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