Azure blob shared key creation 403 error getting

sagar
February 21, 2023
179 views
0 votes
2 Answers

I wanted to create Azure blob container using python code using shared key Authorization,

I am getting below error:

b'xefxbbxbf<?xml version="1.0" encoding="utf-8"?><Error><Code>AuthenticationFailed</Code><Message>Server failed to authenticate the request. Make sure the value of Authorization header is formed correctly including the signature.nRequestId:9e524b5e-301e-0051-4aa4-45750000nTime:2023-02-21T03:27:02.8384023Z</Message><AuthenticationErrorDetail>The MAC signature found in the HTTP request 'xxxxxxxxxxxxxxxx' is not the same as any computed signature. Server used following string to sign: 'PUTnnnnnnnnnnnnx-ms-date:Tue, 21 Feb 2023 03:27:01 GMTnx-ms-version:2020-04-08n/blobmediapedevwus2/mycontainernrestype:container'.</AuthenticationErrorDetail></Error>'

How to fix this?

Below is the python code:

import requests
import datetime
import hmac
import hashlib
import base64

# Set the storage account name and access key
STORAGE_ACCOUNT_NAME = 'vidyaflowerapp01'
STORAGE_ACCOUNT_KEY = "xxxxxxxxxx"

# Set the container name
CONTAINER_NAME = 'test'

# Set the request method and version
REQUEST_METHOD = 'PUT'
REQUEST_VERSION = '2020-04-08'

# Set the request date
REQUEST_DATE = datetime.datetime.utcnow().strftime('%a, %d %b %Y %H:%M:%S GMT')

CANONICALIZED_HEADERS = f'x-ms-date:{REQUEST_DATE}nx-ms-version:{REQUEST_VERSION}n'


# Set the canonicalized resource string
CANONICALIZED_RESOURCE = f'/{STORAGE_ACCOUNT_NAME}/{CONTAINER_NAME}nrestype:container'

VERB = 'PUT'
Content_Encoding = ''
Content_Language = ''
Content_Length = ''
Content_MD5 = ''
Content_Type = ''
Date = ''
If_Modified_Since = ''
If_Match = ''
If_None_Match = ''
If_Unmodified_Since = ''
Range = ''
CanonicalizedHeaders = CANONICALIZED_HEADERS
CanonicalizedResource = CANONICALIZED_RESOURCE

STRING_TO_SIGN = (VERB + 'n' + Content_Encoding + 'n' + Content_Language + 'n' +
                Content_Length + 'n' + Content_MD5 + 'n' + Content_Type + 
                Date + 'n' + If_Modified_Since + 'n' + If_Match + 'n' +
                If_None_Match + 'n' + If_Unmodified_Since + 'n' + Range + 'n' +
                CanonicalizedHeaders + CanonicalizedResource)
signature = base64.b64encode(hmac.new(base64.b64decode(STORAGE_ACCOUNT_KEY), msg=STRING_TO_SIGN.encode('utf-8'), digestmod=hashlib.sha256).digest()).decode()

# Generate the authorization header
auth_header = f'SharedKey {STORAGE_ACCOUNT_NAME}:{signature}'


# Set the request URL
request_url = f'https://{STORAGE_ACCOUNT_NAME}.blob.core.windows.net/{CONTAINER_NAME}?restype=container'

# Set the request headers
request_headers = {
    'x-ms-date': REQUEST_DATE,
    'x-ms-version': REQUEST_VERSION,
    'Authorization': auth_header
}

# Send the request
response = requests.put(request_url, headers=request_headers)
print(response.content)
print(response.status_code)

above code uses shared key Authorization to make request, we have to replace access-key and storage account in order test

Current response: 403
Expected response: 201

Answers

- GauravMantri
- February 21, 2023 at 7:11 am
- 0 votes
0
I believe the reason you are getting this error is because you are setting Content-Length value to 0 in STRING_TO_SIGN however the server is using an empty string when validating the signature (please look at the error details which tells you the string to sign used by server to verify the signature).

From this link:

Please try by setting Content_Length variable to an empty string instead of 0.

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Adding to what @Gaurav Mantri said, You are receiving this as because the authorization headers are not correctly formed. After reproducing from my end, this was working fine when I replace both Date and Content Length with empty string while building the signature. Below is the complete code that worked for me.

import requests
import datetime
import hmac
import hashlib
import base64

# Set the storage account name and access key
STORAGE_ACCOUNT_NAME = '<XXX>'
STORAGE_ACCOUNT_KEY = "<XXX>"

# Set the container name
CONTAINER_NAME = 'mycontainer522'

# Set the request method and version
REQUEST_METHOD = 'PUT'
REQUEST_VERSION = '2020-04-08'

# Set the request date
REQUEST_DATE = datetime.datetime.utcnow().strftime('%a, %d %b %Y %H:%M:%S GMT')

CANONICALIZED_HEADERS = f'x-ms-date:{REQUEST_DATE}nx-ms-version:{REQUEST_VERSION}n'


# Set the canonicalized resource string
CANONICALIZED_RESOURCE = f'/{STORAGE_ACCOUNT_NAME}/{CONTAINER_NAME}nrestype:container'

VERB = 'PUT'
Content_Encoding = ''
Content_Language = ''
Content_Length = ''
Content_MD5 = ''
Content_Type = ''
Date = ''
If_Modified_Since = ''
If_Match = ''
If_None_Match = ''
If_Unmodified_Since = ''
Range = ''
CanonicalizedHeaders = CANONICALIZED_HEADERS
CanonicalizedResource = CANONICALIZED_RESOURCE

STRING_TO_SIGN = (VERB + 'n' + Content_Encoding + 'n' + Content_Language + 'n' +
                Content_Length + 'n' + Content_MD5 + 'n' + Content_Type + 'n' +
                Date + 'n' + If_Modified_Since + 'n' + If_Match + 'n' +
                If_None_Match + 'n' + If_Unmodified_Since + 'n' + Range + 'n' +
                CanonicalizedHeaders + CanonicalizedResource)

# Generate the signature
signature = base64.b64encode(hmac.new(base64.b64decode(STORAGE_ACCOUNT_KEY), msg=STRING_TO_SIGN.encode('utf-8'), digestmod=hashlib.sha256).digest()).decode()

# Generate the authorization header
auth_header = f'SharedKey {STORAGE_ACCOUNT_NAME}:{signature}'


# Set the request URL
request_url = f'https://{STORAGE_ACCOUNT_NAME}.blob.core.windows.net/{CONTAINER_NAME}?restype=container'

# Set the request headers
request_headers = {
    'x-ms-date': REQUEST_DATE,
    'x-ms-version': REQUEST_VERSION,
    'Authorization': auth_header
}

# Send the request
response = requests.put(request_url, headers=request_headers)
print(response.content)
print(response.status_code)

Results:

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