From 27600805e62f800bacf990354632eae4e487d34c Mon Sep 17 00:00:00 2001 From: Yazen Ghannam Date: Thu, 3 Sep 2026 10:43:25 -0500 Subject: x86/amd_node: Fix PCI device reference counting in amd_smn_init() The local "root" pointer is a temporary variable used during the device search. Therefore, refcount related to the search iterators should be cleaned up after the search is complete. Use the __free() cleanup macro to ensure the refcount is decremented when the temporary pointer goes out of scope. Additionally, increment the refcount when caching a root pointer. This ensures the in-use refcount is separate from the temporary search refcounting. Finally, drop the redundant "root = NULL" before the second search loop. The pci_get_class() iterator always decrements the refcount of its "from" argument, so the first loop can only fall through with "root" already NULL. Fixes: 0a4b61d9c2e4 ("x86/amd_node: Fix AMD root device caching") Closes: https://sashiko.dev/#/patchset/20260806160159.230453-1-jason.andryuk%40amd.com Reported-by: Sashiko Assisted-by: LLM Signed-off-by: Yazen Ghannam Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Mario Limonciello (AMD) Cc: Link: https://patch.msgid.link/20260903154325.74343-1-yazen.ghannam@amd.com --- lib/crypto/mpi/mpi-div.c | 230 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 230 insertions(+) create mode 100644 lib/crypto/mpi/mpi-div.c (limited to 'lib/crypto/mpi/mpi-div.c') diff --git a/lib/crypto/mpi/mpi-div.c b/lib/crypto/mpi/mpi-div.c new file mode 100644 index 000000000..6e5044e72 --- /dev/null +++ b/lib/crypto/mpi/mpi-div.c @@ -0,0 +1,230 @@ +/* mpi-div.c - MPI functions + * Copyright (C) 1994, 1996, 1998, 2001, 2002, + * 2003 Free Software Foundation, Inc. + * + * This file is part of Libgcrypt. + * + * Note: This code is heavily based on the GNU MP Library. + * Actually it's the same code with only minor changes in the + * way the data is stored; this is to support the abstraction + * of an optional secure memory allocation which may be used + * to avoid revealing of sensitive data due to paging etc. + */ + +#include "mpi-internal.h" +#include "longlong.h" + +int mpi_tdiv_qr(MPI quot, MPI rem, MPI num, MPI den); + +int mpi_fdiv_r(MPI rem, MPI dividend, MPI divisor) +{ + int divisor_sign = divisor->sign; + MPI temp_divisor = NULL; + int err; + + /* We need the original value of the divisor after the remainder has been + * preliminary calculated. We have to copy it to temporary space if it's + * the same variable as REM. + */ + if (rem == divisor) { + temp_divisor = mpi_copy(divisor); + if (!temp_divisor) + return -ENOMEM; + divisor = temp_divisor; + } + + err = mpi_tdiv_r(rem, dividend, divisor); + if (err) + goto free_temp_divisor; + + if (((divisor_sign?1:0) ^ (dividend->sign?1:0)) && rem->nlimbs) + err = mpi_add(rem, rem, divisor); + +free_temp_divisor: + mpi_free(temp_divisor); + + return err; +} + +/* If den == quot, den needs temporary storage. + * If den == rem, den needs temporary storage. + * If num == quot, num needs temporary storage. + * If den has temporary storage, it can be normalized while being copied, + * i.e no extra storage should be allocated. + */ + +int mpi_tdiv_r(MPI rem, MPI num, MPI den) +{ + return mpi_tdiv_qr(NULL, rem, num, den); +} + +int mpi_tdiv_qr(MPI quot, MPI rem, MPI num, MPI den) +{ + mpi_ptr_t np, dp; + mpi_ptr_t qp, rp; + mpi_size_t nsize = num->nlimbs; + mpi_size_t dsize = den->nlimbs; + mpi_size_t qsize, rsize; + mpi_size_t sign_remainder = num->sign; + mpi_size_t sign_quotient = num->sign ^ den->sign; + unsigned int normalization_steps; + mpi_limb_t q_limb; + mpi_ptr_t marker[5]; + int markidx = 0; + int err; + + /* Ensure space is enough for quotient and remainder. + * We need space for an extra limb in the remainder, because it's + * up-shifted (normalized) below. + */ + rsize = nsize + 1; + err = mpi_resize(rem, rsize); + if (err) + return err; + + qsize = rsize - dsize; /* qsize cannot be bigger than this. */ + if (qsize <= 0) { + if (num != rem) { + rem->nlimbs = num->nlimbs; + rem->sign = num->sign; + MPN_COPY(rem->d, num->d, nsize); + } + if (quot) { + /* This needs to follow the assignment to rem, in case the + * numerator and quotient are the same. + */ + quot->nlimbs = 0; + quot->sign = 0; + } + return 0; + } + + if (quot) { + err = mpi_resize(quot, qsize); + if (err) + return err; + } + + /* Read pointers here, when reallocation is finished. */ + np = num->d; + dp = den->d; + rp = rem->d; + + /* Optimize division by a single-limb divisor. */ + if (dsize == 1) { + mpi_limb_t rlimb; + if (quot) { + qp = quot->d; + rlimb = mpihelp_divmod_1(qp, np, nsize, dp[0]); + qsize -= qp[qsize - 1] == 0; + quot->nlimbs = qsize; + quot->sign = sign_quotient; + } else + rlimb = mpihelp_mod_1(np, nsize, dp[0]); + rp[0] = rlimb; + rsize = rlimb != 0?1:0; + rem->nlimbs = rsize; + rem->sign = sign_remainder; + return 0; + } + + err = -ENOMEM; + if (quot) { + qp = quot->d; + /* Make sure QP and NP point to different objects. Otherwise the + * numerator would be gradually overwritten by the quotient limbs. + */ + if (qp == np) { /* Copy NP object to temporary space. */ + np = marker[markidx++] = mpi_alloc_limb_space(nsize); + if (!np) + goto out_free_marker; + MPN_COPY(np, qp, nsize); + } + } else /* Put quotient at top of remainder. */ + qp = rp + dsize; + + normalization_steps = count_leading_zeros(dp[dsize - 1]); + + /* Normalize the denominator, i.e. make its most significant bit set by + * shifting it NORMALIZATION_STEPS bits to the left. Also shift the + * numerator the same number of steps (to keep the quotient the same!). + */ + if (normalization_steps) { + mpi_ptr_t tp; + mpi_limb_t nlimb; + + /* Shift up the denominator setting the most significant bit of + * the most significant word. Use temporary storage not to clobber + * the original contents of the denominator. + */ + tp = marker[markidx++] = mpi_alloc_limb_space(dsize); + if (!tp) + goto out_free_marker; + mpihelp_lshift(tp, dp, dsize, normalization_steps); + dp = tp; + + /* Shift up the numerator, possibly introducing a new most + * significant word. Move the shifted numerator in the remainder + * meanwhile. + */ + nlimb = mpihelp_lshift(rp, np, nsize, normalization_steps); + if (nlimb) { + rp[nsize] = nlimb; + rsize = nsize + 1; + } else + rsize = nsize; + } else { + /* The denominator is already normalized, as required. Copy it to + * temporary space if it overlaps with the quotient or remainder. + */ + if (dp == rp || (quot && (dp == qp))) { + mpi_ptr_t tp; + + tp = marker[markidx++] = mpi_alloc_limb_space(dsize); + if (!tp) + goto out_free_marker; + MPN_COPY(tp, dp, dsize); + dp = tp; + } + + /* Move the numerator to the remainder. */ + if (rp != np) + MPN_COPY(rp, np, nsize); + + rsize = nsize; + } + + q_limb = mpihelp_divrem(qp, 0, rp, rsize, dp, dsize); + + if (quot) { + qsize = rsize - dsize; + if (q_limb) { + qp[qsize] = q_limb; + qsize += 1; + } + + quot->nlimbs = qsize; + quot->sign = sign_quotient; + } + + rsize = dsize; + MPN_NORMALIZE(rp, rsize); + + if (normalization_steps && rsize) { + mpihelp_rshift(rp, rp, rsize, normalization_steps); + rsize -= rp[rsize - 1] == 0?1:0; + } + + rem->nlimbs = rsize; + rem->sign = sign_remainder; + + err = 0; + +out_free_marker: + while (markidx) { + markidx--; + mpi_free_limb_space(marker[markidx]); + } + + return err; +} -- cgit v1.3.1