62 lines
1.8 KiB
Bash
Executable File
62 lines
1.8 KiB
Bash
Executable File
#!/bin/sh
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# Set Content-Type for CGI script
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echo "Content-type: application/json"
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echo ""
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# Read POST data
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read -r POST_DATA
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# Debug log for generated hash
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DEBUG_LOG="/tmp/auth.log"
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# Extract the password from POST data (URL encoded)
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USER="root"
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INPUT_PASSWORD=$(echo "$POST_DATA" | grep -o 'password=[^&]*' | cut -d= -f2-)
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# URL-decode the password while preserving most special characters
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# First decode percent-encoded sequences
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urldecode() {
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local encoded="${1//+/ }"
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printf '%b' "${encoded//%/\\x}"
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}
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# Decode the password
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INPUT_PASSWORD=$(urldecode "$INPUT_PASSWORD")
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# Basic validation to reject & and $ characters
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if echo "$INPUT_PASSWORD" | grep -q '[&$]'; then
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echo '{"state":"failed", "message":"Password contains forbidden characters (& or $)"}'
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exit 1
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fi
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# Sanitize the password for shell usage
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INPUT_PASSWORD=$(printf '%s' "$INPUT_PASSWORD" | sed 's/[\"]/\\&/g')
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# Extract the hashed password from /etc/shadow for the specified user
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USER_SHADOW_ENTRY=$(grep "^$USER:" /etc/shadow)
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if [ -z "$USER_SHADOW_ENTRY" ]; then
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echo '{"state":"failed", "message":"User not found"}'
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exit 1
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fi
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# Extract the password hash (it's the second field, colon-separated)
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USER_HASH=$(echo "$USER_SHADOW_ENTRY" | cut -d: -f2)
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# Extract the salt (MD5 uses the $1$ prefix followed by the salt)
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SALT=$(echo "$USER_HASH" | cut -d'$' -f3)
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# Generate a hash from the input password using the same salt
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# Use printf to avoid issues with special characters in echo
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GENERATED_HASH=$(printf '%s' "$INPUT_PASSWORD" | openssl passwd -1 -salt "$SALT" -stdin)
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# Log generated hash for debugging
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printf "Generated hash: %s\n" "$GENERATED_HASH" >> "$DEBUG_LOG"
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# Compare the generated hash with the one in the shadow file
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if [ "$GENERATED_HASH" = "$USER_HASH" ]; then
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echo '{"state":"success"}'
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else
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echo '{"state":"failed", "message":"Authentication failed"}'
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fi |