mbedtls: security bump to version 2.28.7

This release of Mbed TLS provides bug fixes and minor enhancements. This
release includes fixes for following security issues:

* Timing side channel in private key RSA operations (CVE-2024-23170)

  Mbed TLS is vulnerable to a timing side channel in private key RSA
  operations. This side channel could be sufficient for an attacker to
  recover the plaintext. A local attacker or a remote attacker who is
  close to the victim on the network might have precise enough timing
  measurements to exploit this. It requires the attacker to send a large
  number of messages for decryption.

* Buffer overflow in mbedtls_x509_set_extension() (CVE-2024-23775)

  When writing x509 extensions we failed to validate inputs passed in to
  mbedtls_x509_set_extension(), which could result in an integer overflow,
  causing a zero-length buffer to be allocated to hold the extension. The
  extension would then be copied into the buffer, causing a heap buffer
  overflow.

Fixes: CVE-2024-23170, CVE-2024-23775
References: https://mbed-tls.readthedocs.io/en/latest/security-advisories/mbedtls-security-advisory-2024-01-1/
References: https://mbed-tls.readthedocs.io/en/latest/security-advisories/mbedtls-security-advisory-2024-01-2/
Signed-off-by: orangepizza <tjtncks@gmail.com>
Signed-off-by: Petr Štetiar <ynezz@true.cz> [formal fixes]
(cherry picked from commit 920414ca88)

package/libs/mbedtls/Makefile

@@ -8,13 +8,13 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=mbedtls
-PKG_VERSION:=2.28.5
+PKG_VERSION:=2.28.7
 PKG_RELEASE:=2
 PKG_BUILD_FLAGS:=no-mips16 gc-sections no-lto
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
 PKG_SOURCE_URL:=https://codeload.github.com/ARMmbed/mbedtls/tar.gz/v$(PKG_VERSION)?
-PKG_HASH:=849e86b626e42ded6bf67197b64aa771daa54e2a7e2868dc67e1e4711959e5e3
+PKG_HASH:=1df6073f0cf6a4e1953890bf5e0de2a8c7e6be50d6d6c69fa9fefcb1d14e981a
 
 PKG_LICENSE:=GPL-2.0-or-later
 PKG_LICENSE_FILES:=gpl-2.0.txt